Hi all,

I have a '97 Grand Cherokee with 2WD and a 4.0 engine.

I am having problems with the car occasionally stalling when at idle. I'll try to bullet my findings thus far:

As background, I commute on the LA freeway about 1.5 hours each way every day. Probably the first 10 minutes of this is city driving. The next 10 is freeway at normal freeway speeds. The next 30-35 is stop and go, the rest is at normal freeway speeds.

When I stop on the freeway (or in town, for that matter) during the "trouble period", it pretty much idles roughly, tries to die, sometimes does, sometimes does not.

1) This happens only from startup to approximately 35-45 minutes of driving time (my "trouble period"). After this time driving, the car works fine (a bit rougher than in the old days, but I just figured that was due to old age...it hasn't really changed in the past year).

2) Sometimes it idles fine, most times rough, every once in a while it dies. Usually it starts right up when I restart it, and resumes operation as is typical during the "problem period". Every once in a while (twice a week?) it takes a while trying. During this time it may (a) turn over quickly without catching for about 20 seconds or so (b) start and idle extremely roughly, and making a smell not really like fuel, but not really like "clean exhaust" either or (c) start right back up after turning over a few seconds.

3) While idling, when I change between drive and park, or neutral, the RPM's go down, then back up. I notice this more markedly going from drive to neutral or park, not so much going back the other way.

4) If I give it gas when it starts to die, it usually picks back up and goes on as before. Every once in a great while, the extra pedal results in what sounds like "dieseling", and it will either work through that and run again as usual, or will die and I'll have to restart it. Most times the extra pedal puts things right again.

5) I seem to be getting better gas mileage since the problem has become more regular. over the past year, my mileage went down (according to the on-board computer) to average about 14.6 or so. For the past couple weeks, since the problem has grown more persistent and regular, my MPG is closer to 15.8 or so (sound like I'm running leaner, right?).

6) I just replaced the IAC motor, thinking from the many, many, many forum threads on this type of issue would suggest, but it made absolutely no difference.

7) The problems seems more likely to occur when the temperature of the outside air at startup time is about 65 or so. The past two days it has been at 80 degrees or above here, and there really hasn't been a time when the car actually felt like it was going to die (though it runs poorly enough to be noticed that something is still not "right"). This is interesting to me because the problem goes away (the idle issue, not so much the not-quite-right running) also after 45 minutes of driving.

I don't think the issue is related to ENGINE temperature, because it has LONG since gotten to regular operating temperature by the time 45 minutes of driving has gone by.

My thoughts are, in order of the likely order of parts replacement (a) The MAP sensor and (b) the coil.

I don't think it is the TPS, because there is no "dead spot" in the range of pedal travel.

I am thinking MAP sensor because the poor performance seems to be during times of low engine load. My understanding (limited as it is) of the MAP sensor is that it is a glorified VACUUM guage. And indeed, the way the jeep is running reminds me of the way my '67 Cougar runs when there is a vacuum leak (at least at idle).

Any thoughts? Hopefully I have provided enough info for someone to think to themselves "Mine did that, the poor bastard needs to replace his jeep's xxxxx" where xxxxx is the part to replace. *LOL*

Hi all,

I have a '97 Grand Cherokee with 2WD and a 4.0 engine.

I am having problems with the car occasionally stalling when at idle. I'll try to bullet my findings thus far:

As background, I commute on the LA freeway about 1.5 hours each way every day. Probably the first 10 minutes of this is city driving. The next 10 is freeway at normal freeway speeds. The next 30-35 is stop and go, the rest is at normal freeway speeds.

When I stop on the freeway (or in town, for that matter) during the "trouble period", it pretty much idles roughly, tries to die, sometimes does, sometimes does not.

1) This happens only from startup to approximately 35-45 minutes of driving time (my "trouble period"). After this time driving, the car works fine (a bit rougher than in the old days, but I just figured that was due to old age...it hasn't really changed in the past year).

2) Sometimes it idles fine, most times rough, every once in a while it dies. Usually it starts right up when I restart it, and resumes operation as is typical during the "problem period". Every once in a while (twice a week?) it takes a while trying. During this time it may (a) turn over quickly without catching for about 20 seconds or so (b) start and idle extremely roughly, and making a smell not really like fuel, but not really like "clean exhaust" either or (c) start right back up after turning over a few seconds.

3) While idling, when I change between drive and park, or neutral, the RPM's go down, then back up. I notice this more markedly going from drive to neutral or park, not so much going back the other way.

4) If I give it gas when it starts to die, it usually picks back up and goes on as before. Every once in a great while, the extra pedal results in what sounds like "dieseling", and it will either work through that and run again as usual, or will die and I'll have to restart it. Most times the extra pedal puts things right again.

5) I seem to be getting better gas mileage since the problem has become more regular. over the past year, my mileage went down (according to the on-board computer) to average about 14.6 or so. For the past couple weeks, since the problem has grown more persistent and regular, my MPG is closer to 15.8 or so (sound like I'm running leaner, right?).

6) I just replaced the IAC motor, thinking from the many, many, many forum threads on this type of issue would suggest, but it made absolutely no difference.

7) The problems seems more likely to occur when the temperature of the outside air at startup time is about 65 or so. The past two days it has been at 80 degrees or above here, and there really hasn't been a time when the car actually felt like it was going to die (though it runs poorly enough to be noticed that something is still not "right"). This is interesting to me because the problem goes away (the idle issue, not so much the not-quite-right running) also after 45 minutes of driving.

I don't think the issue is related to ENGINE temperature, because it has LONG since gotten to regular operating temperature by the time 45 minutes of driving has gone by.

My thoughts are, in order of the likely order of parts replacement (a) The MAP sensor and (b) the coil.

I don't think it is the TPS, because there is no "dead spot" in the range of pedal travel.

I am thinking MAP sensor because the poor performance seems to be during times of low engine load. My understanding (limited as it is) of the MAP sensor is that it is a glorified VACUUM guage. And indeed, the way the jeep is running reminds me of the way my '67 Cougar runs when there is a vacuum leak (at least at idle).

Any thoughts? Hopefully I have provided enough info for someone to think to themselves "Mine did that, the poor bastard needs to replace his jeep's xxxxx" where xxxxx is the part to replace. *LOL*


This sounds just like a bad IAC Valve - 1 did you disconnect the battery before you removed/replaced the IAC Valve? 2 did you adjust it according to the instructions?

This sounds just like a bad IAC Valve - 1 did you disconnect the battery before you removed/replaced the IAC Valve? 2 did you adjust it according to the instructions? Yeah, that's what I thought, and why I replaced that part first. *L* Oh well...

Yeah, I did disconnect the battery, for probably about a half hour, give or take. During the time I replaced the IAC motor, anyway.

I followed the instructions, but all they really said was "if it sticks out more than <yada,yada> inches, then you need to adjust it smaller (can't remember what the <yada,yada> was...might have been 1 1/8 inches), but the plunger was shorter than that, and since it didn't say to make it that long, I left it shorter (as it came from the parts place).

I put on a NAPA IAC, thinking they generally have the better OTC parts than places like AutoZone, Kragen, or Pep Boys. Is this something that is better purchased from the dealer?

Interestingly enough, though it does not yet run like it should, the past two days I have driven it, it has not died at idle on the freeway. I can still feel it running rough(er than usual) but it does not stumble and die (at least so far). Could it be that the computer is learning how to set itself after several days? I know that to "clear" the computer's memory about current settings from sensors is why the battery is disconnected, but would not expect the "learning" to result in the initial reconnection of battery and driving after the IAC motor replacement to take this long.

I'll see how it does on the way home (and until payday!) but am just curious about (assuming it is not yet fixed) the deal with NAPA verses Dealership purchase for this part (I usually get sensors from the dealer, just to be safe, this time I thought I'd try NAPA).

Thanks for your input so far!!!

I was also thinking....what about the engine temp sensor on the front of the engine? I understand (from forums and many online searches) that there is a separate engine temp sensor for the 'puter and a different one for the gauge? Hmmmm....So, you're saying cold idle is too low? Runs OK after it warms up? If so, check out the engine temp sensor on the front of the engine--the one that feeds the ECM. The one on the back of the head feeds the temp sensor--at least that's where the are on the early 4.0's.
The ECM varies fuel mixture proportionately to the resistance of the temp sensor--it's the modern-day equivalent of a choke--cold engine=more fuel. As the engine warms up, the extra fuel is reduced. The temp sensor is also instrumental in setting cold idle speed. Cold engine=high idle.
Without cold enrichment and higher idle speed, you could experience stumble and hesitation until the engine warms up.Does this sound plausible?

I suppose I could look into the book and see where it is. If I'm just tossing money at it (no C.E.S. light/codes, no data sniffer) maybe the temp sensor would be a cheaper option to check than getting a new dealer-supplied IAC?

Any thoughts?

The only thing that makes me hesitate on this one is that it continues for quite a while after the gauge on the dash says I have reached operating temperature.

I was also thinking....what about the engine temp sensor on the front of the engine? I understand (from forums and many online searches) that there is a separate engine temp sensor for the 'puter and a different one for the gauge? Hmmmm....Does this sound plausible?

I suppose I could look into the book and see where it is. If I'm just tossing money at it (no C.E.S. light/codes, no data sniffer) maybe the temp sensor would be a cheaper option to check than getting a new dealer-supplied IAC?

Any thoughts?

The only thing that makes me hesitate on this one is that it continues for quite a while after the gauge on the dash says I have reached operating temperature.


I doubt it's the temp sensor. What do you mean by "no C.E.S. light/codes, no data sniffer"?

I don't think you got a bad part from NAPA, although plausible, they are relatively good parts, did the part have a warranty ussually electrical parts like this carry a 90 warranty, if so I would take it back get a new one, and this time set the IAC valve at 1 1/8" from the inside of the pating surface to the tip of the plunger. Even if it didn't have a warranty it is a good idea to disconnect the battery, pull the IAC Valve off, check on the inside of the IAC bore for any dirt or carbon build up and set the AIC at 1 1/8".

I doubt it's the temp sensor. What do you mean by "no C.E.S. light/codes, no data sniffer"?

I don't think you got a bad part from NAPA, although plausible, they are relatively good parts, did the part have a warranty ussually electrical parts like this carry a 90 warranty, if so I would take it back get a new one, and this time set the IAC valve at 1 1/8" from the inside of the pating surface to the tip of the plunger. Even if it didn't have a warranty it is a good idea to disconnect the battery, pull the IAC Valve off, check on the inside of the IAC bore for any dirt or carbon build up and set the AIC at 1 1/8".
I just mean no "Service Engine Soon" (just added the "C" to the beginning to throw you off *blush*) or a reader to read any codes that might be there but not setting off the SES light on the dash.

Unfortunately, I tossed both the isntructions and the reciept, since I was POSITIVE this was the issue (you'd think I'da learned after many newer cars and 3 classic car restorations to keep that stuff until it is verified "fixed", but I guess everyone needs to be stupid once in a while).

I will do the IAC thing (disconnect battery, take it off, adjust to 1-1/8", reinstall, reconnect)...MAY have to wait until this weekend (or until it leaves me stranded at the side of the road *LOL*)...I have no garage light at the moment...and it's been getting dark pretty early these past coupla weeks.

Okee-dokee, back again.

I finally got back to it last weekend and took out the new sensor, scrubbed and cleaned the #@$)(*@# out of the IAC body, readjusted the plunger, and stuck it back in.

Alas, no change.

So, now it is starting to die/falter more often. So I suppose sooner or later it will leave me stranded and then I will know for sure what it is *LOL* Hopefully y'all can help me before I get to that point.

Lately it has started to stumble and almost stall when I come to a stop even after over an hour and a half of driving. When I am at-speed, there don't seem to be any problems.

A couple nights ago, I took off and just after leaving the curb it died. I started back up right away. Then about another 10 yards down the road, it died. Had to crank it for a loooong time this time before it started up. Drove around the corner, it sputters, diesels for a few long seconds, then died. I tried to start it, but no go. I smell fuel...feels and smells like a flooded engine. So I wait. try it again after a minute or so. No start...lots of turning over, no start. So I wait again, and start thinking about reaching for my Auto Club card. Try again, it starts up. Before I leave the curb, it starts dieseling again. I cut the ignition off (noticing that it seems to take longer to start up after a incidence of the dieseling - as opposed to an easy start after it just dies without dieseling) I decide to tempt fate and go on my merry way. Travelling along at 20-25, it sputters a few times, then runs fine. More sputtering for the next couple miles. Then it is fine for the remainder of my drive time, and even while waiting in line in the KFC drive-through and idling.

When the car does it's Dieseling thing after sputtering and trying to decide if it wants to die or not, I can sometimes smell a faint odor of gas, but more often an odd burnt smell that is probably partially burnt fuel? I dunno. Odd smell, but I assume gas and exhaust.

I think at this time maybe it's an ignition-side issue, because it seems like ignition when it gets to dieseling when it faulters - though sometimes it just dies without the dieseling.

I am almost to the point of taking it to a repair shop, but I am afraid they will just fix by replacement - - I have no idea if non-dealer shops can use a computer reader machine sufficiently well to diagnose the actual problem.

I would much rather fix myself if possible (obviously).

This weekend I am thinking of replacing the Coil and/or the Crankshaft position sensor, but really hate to toss money after parts.

I don't know if a bad IAC could cause the dieseling.

It's possible that the new IAC is bad, I suppose, or that I messed it up by not adjusting it to 1-1/8 inches initially, then doing that adjustment the second time around (especially since when I took it out the second time it was extended more than it was when I put it in new). I'm afraid it's possible that I adjusted it to be too SHORT now, to close all the way...but if so, I don't know if that would cause my current issues.

I don't mind re-replacing the IAC if that sounds like it could still be the issue, but every time I see something on a forum about this problem, I think "hey, yeah, that sounds like it could be the problem" and then the more I think about it, it doesn't quite fit with my issue.

On a separate, related issue...one time during the battle on the way to KFC (LOL) I did see the orange square light up in the engine part of the on-board-display console above my console, but it quickly turned off, and no text was displayed in the brief interval when the box was illuminated on the display.

It is a '97 JGC with the 4.0 (as I previously said) and I have tried to do the key on/off/on/off/on/off/on thing to get the error codes to display on my odometer, but it doesn't display anything, it just sits there. smirking. smirking and pointing at me.

Thoughts?

Thanks!
Paul

this thread (http://www.automotiveforums.com/vbulletin/showthread.php?t=634110) sounds alot like mine.

If it IS the CPS, is there any good reason to get the part from the jeep dealer? I am so used to dealing with my classic cars that mostly don't HAVE dealership parts anymore, that I don't know if these types of sensors are reliable from aftermarket (aka, pep boys, NAPA) or if I need to bite the bullet and get one from the dealership?

this thread (http://www.automotiveforums.com/vbulletin/showthread.php?t=634110) sounds alot like mine.

If it IS the CPS, is there any good reason to get the part from the jeep dealer? I am so used to dealing with my classic cars that mostly don't HAVE dealership parts anymore, that I don't know if these types of sensors are reliable from aftermarket (aka, pep boys, NAPA) or if I need to bite the bullet and get one from the dealership? Hi Paul! I emailed you the fix for my misfiring on my 1997,2wd,4.0 via private email, but wanted to also list this fix for anyone else out there experiencing this problem of hesitation, stumbling, backfire,dies or almost dies, starts right back up or have to wait a little while, funny carbon burn/gas/exhaust fumes smell senario.
I did two things and of the two don't know which one fixed it. The first thing was to buy a 32 oz. bottle of Marvel Mystery Oil and added 8oz to 10gal of gas, and 16oz. to the oil in the crankcase. Also, the second thing was take ou all the fuses(one at a time) in the engine compartment, and clean off the fuse legs with alcohol and 3m scotchbrite to make them shinny and metallic looking since they looked brown and corroded. After doing that within 3 days of driving now I have not had one missfire or any hesitation. Hope this helps, it sure made a believer out of me after having spent nearly $700 on CPS, Camshaft PS, new distributor, sparkplugs & wires, new fuel pump, screens, and regulator, new catalytic converter, IAC, and new coil---All OEM Mopar parts!!! To be honest, I think the main problem all along was either dirty injectors, or sticking valves, making sense why the Mystery Oil worked to fix it; or a short from time to time in the fusible ignition system since the fuses were corroded and dropped signals to the PCM intermittently. I hope this helps out there, because this problem is a tricky one and very tuff to fix.
Good luck and God bless, Happy Thanksgiving! Speck

ive had the smae problem for a while, the dealer ran a diagnostic and it came up with O2 sesor, so i replaced it and my jeep still dies, so i ran one and the local high school auto shop and that came up with computer chip and ignition coil, i have a brand new ignition coil so i doubt it is tghe problem. but im having a computer shipped to my house right now.

and my engine is to the pont were i ujnplug my O2 sensors and it runs better, but i had no O2 sensors when i bought it to begin with.

ive had the smae problem for a while, the dealer ran a diagnostic and it came up with O2 sesor, so i replaced it and my jeep still dies, so i ran one and the local high school auto shop and that came up with computer chip and ignition coil, i have a brand new ignition coil so i doubt it is tghe problem. but im having a computer shipped to my house right now.

and my engine is to the pont were i ujnplug my O2 sensors and it runs better, but i had no O2 sensors when i bought it to begin with.Hi! I read your entry--what code was coming up that the dealer put a O2 sensor in? Studmuffin and I were both having a 43 code meaning multiple misfires, and that is the code using our OBD in the Jeep. However, if a 43 code comes up you need to take it to Autozone for a free scan to isolate that code, because within the 43 code are sub/scan codes P0300-P0308; P0300 meaning misfire in all the cylinders, and subsequent codes 301-308 standing for the actual cylinder that alone is misfiring--so P0304 means that cylinder 4 is causing the problem. The problem is either a dirty fuel injector, bad injector, or a sticking valve, usually. Hope this helps! Let me know if the replacement of the PCM fixes your problem. Remember, after installing the new PCM you will need to take it to a dealer to program it to your particular car. Get back to me with your results. Speck

Hi! I read your entry--what code was coming up that the dealer put a O2 sensor in? Studmuffin and I were both having a 43 code meaning multiple misfires, and that is the code using our OBD in the Jeep. However, if a 43 code comes up you need to take it to Autozone for a free scan to isolate that code, because within the 43 code are sub/scan codes P0300-P0308; P0300 meaning misfire in all the cylinders, and subsequent codes 301-308 standing for the actual cylinder that alone is misfiring--so P0304 means that cylinder 4 is causing the problem. The problem is either a dirty fuel injector, bad injector, or a sticking valve, usually. Hope this helps! Let me know if the replacement of the PCM fixes your problem. Remember, after installing the new PCM you will need to take it to a dealer to program it to your particular car. Get back to me with your results. Speck

i work at advance auto parts, thats were i pulled the code from.

I put the 02 sensor in myself.

And usually chrystler pcms program themselves, in my stepdads 97 grand cherokee he replaced the computer and it ran fine after like 2 days of runnin it, his mother and sister works for the local jeep dealership, thats who told us about it.

and ive put fuel injector cleaner in my fuel numerous times, many diffrent types too, so if they work the valves shoule be pretty clean.

i bought this jeep as a POS for $2,500. and it diddnt run after a month.
ive owned it for a year, putting almost $7,000 into it, this pcm will break the $7,000. and i dont mind putting money into it or working on it, cuz i love my jeep, but im sick of ot having an unreliable ride.

hopefully the PCM works.

Howdy all, back again. Hey Speck1, I appreciate the info in emails and on here. I don't think our problems are exactly the same (for example, you said your car misfired and/or died at speed, but mine only does so at idle, or for a time there, just starting out from the curb or at very low speeds - - also, I have not gotten any codes at all from my JGC - I don't have a reader and cannot seem to make the car cough up the codes using the key on/off thing, and it does not light the Check Engine light), but will try the mystery oil and fuse cleaning, I mean, what can it hurt, right? *L*

This past weekend I replaced the CPS (which took a total of about 20 minutes, thanks to the suggestions and guidelines elsewhere on this site!!!) and it runs MUCH better now. It has only died at idle once, and I no longer seem to get the misfires before it dies (or the one time it died). I still know something else is wrong, but either the CPS replacement, or the resetting of the computer from unhooking the battery, seems to have helped considerably.

Now it still idles roughly when it warms up, or when I am stuck in traffic. At speed it runs like a top, no issues. After about 30 minutes of driving, it also has no problem dropping down to an idle and staying at around 750 on the tach (which is where it typically idles).

I think it may be the IAC yet. I couple weekends ago, I took the NAPA IAC out again and re-adjusted it...but that may have screwed it up more, as I noticed it was positioned outward (the pintel) farther than it was when I initially installed it, and if I adjusted it inward more (back down to 1-1/8 inches) then I fear I may have adjusted it too far in, and the motor is unable to push the pintle out far enough when it needs to. I don't know.

Further, I have been playing around with it at idle a bit, trying to get clues about what is up with it. I have found that sitting there at idle, if I turn the air conditioning off, the engine stumbles and nearly dies, then catches again and idles at 750. If I turn the A/C back on, then the idle speeds up (as it should) and then settles down again to around 750. I can reproduce this effect at will simply by turning the A/C on and off.

It really seems to me that the IAC is just not responding FAST enough sometimes. Now I wonder if the times it has died recently in traffic at idle, if the A/C just happened to cycle off at that moment? Hmmmm....hard to catch that one. But whatever the issue is, it seems to be directly affected by turning my A/C on and off (turning the power steering left or right does not seem to have an effect).

To me this issue and the A/C thing points at the IAC. So, probably this weekend (unless anyone else shows me the error of my ways before then) I will get a new IAC from the dealer and see where that gets me.

Well, Speckster...now I'm with you.

For the first time since this started happening, I was finally able to go freeway speeds the whole way to work (hey, it is the 405 corridor in LA!), and actually finally had it cut out on me at about 70 MPH!!! WTF???

Still at about the same time period into the drive (around 30 minutes or so) from where I got on the road this morning. Probably my imagination, but it seems more time-related than anything at this point *LOL*

After I flipped into Neutral and restarted it, it continued on the way just fine the rest of the trip to work (another 20 minutes or so). Once to work, I idled a while in the parking lot, and it would run fine, then stumble, then run fine, then race a bit, then run fine.

...as I listened to this, I could hear the A/C cycling on and off also. So at least THAT part (the intermittent stumbling at idle) is very definately related to the A/C coming on and off. THAT must be the IAC, I would think (other thoughts welcomed, however!).

Still cannot figure why the IAC would have anything to do with causing the engine to die at 70 MPH though...so probably I am dealing with two different issues.?!?!?

I put the MMO in last night. Will try to clean the fuses this weekend. Sure would like to fix this without throwing $700 worth of parts at the bugger.

Well, Speckster...now I'm with you.

For the first time since this started happening, I was finally able to go freeway speeds the whole way to work (hey, it is the 405 corridor in LA!), and actually finally had it cut out on me at about 70 MPH!!! WTF???

Still at about the same time period into the drive (around 30 minutes or so) from where I got on the road this morning. Probably my imagination, but it seems more time-related than anything at this point *LOL*

After I flipped into Neutral and restarted it, it continued on the way just fine the rest of the trip to work (another 20 minutes or so). Once to work, I idled a while in the parking lot, and it would run fine, then stumble, then run fine, then race a bit, then run fine.

...as I listened to this, I could hear the A/C cycling on and off also. So at least THAT part (the intermittent stumbling at idle) is very definately related to the A/C coming on and off. THAT must be the IAC, I would think (other thoughts welcomed, however!).

Still cannot figure why the IAC would have anything to do with causing the engine to die at 70 MPH though...so probably I am dealing with two different issues.?!?!?

I put the MMO in last night. Will try to clean the fuses this weekend. Sure would like to fix this without throwing $700 worth of parts at the bugger.Hi Muffinator! I,m not glad you had to experience this cutout and dieseling at 70mph, but it sure does point to the fact that we have very similar issues. Yes, I have had issues at "idle", like you described, I've had issues at just about every speed without warning--it just starts misfiring, stumbling, and dieseling wanting to die out and then just picks up and runs like a champ! Or, it may die out, but will restart right away, maybe stumble again, then run fine the rest of the trip. Whenever it starts this weird action, I know it well and can anticipate it, I usually put it in neutral and push several quick times on the acclerator and it usually picks up and runs fine.
The one thing I can state for sure, is that it does not ever, ever happen until I have been driving for between 15-30 minutes. So, I keep thinking what can take sooooo looong to warm up?
After writing you last time about the MMO, and cleaning the fuses, I have not had one problem------until today! Ugh! But I was pulling my 18 foot center counsel offshore fishing boat uphill at about 50mph and it misfired a couple of times---but did not die out! So, I continue to add MMO to my gas hoping that maybe there is still some carbon on my valves?
Being that we live in somewhat similar climates, I live in Daytona Beach,FL area, maybe heat is a common denominator. Whatever, I am groping somewhat because this problem is actually getting to me now. My wife says to trade it in, but it looks like new and has been probably the most reliable vehicle we have owned! It has 235K on it and really does drive nicely. They wouldn't give me much on a trade---that's why if I can solve this one problem--I'm home free for a long time to come.
Let me ask you---have you replaced the PCM yet? I have been talking to others on the net and can't remember if you have done that. It seems like most all those that have--- resulted in a no/fix situation, or a worse problem at best.
The only thing that bugs me is that you are not able to pull up a trouble code on your onboard diagnostics!!! By turning the key on and off three times quickly and then the 4th time just turn it on (not start) and leave it there it should cycle a 12, then some code, and end with 55. Mine always comes up with a 43 code--multiple misfires. The check engine light does not come on, but after an experience with a bad stumble/dieseling/dying-- when I get to my destination, I will turn the car off and do this on/off thing to pull up this same code everytime. I disconnect the battery to cancel the code from memory so it just shows a 12, then 55 and know the code is not there, and it stays gone until I have another prob. I took it to Autozone after an episode with the 43 code in there and they scanned a PO351 code which states a problem in the primary or secondary ignition system. Well, I have replaced (2 times now) everything in these systems. So, I am really "lost"---maybe I should sign on to the TV series and join everybody else on that island--because I would fit right in! Ha!
Anyone else out there that could be of any assistance would be greatly appreciated!!!!!! Would really hate to give in to my wife's idea to trade--it sounds like a macho thing, but not really--just want my Jeep back to 100%. If anyone out there has found a "true fix for good", please, please take a minute and say hello. Thanks, Speck--getting desperate!!

Nope, I have not considered replacing the PCM as of yet. That seems like a last resort to me. I did replace the IAC motor again this morning, with a MOPAR part (had already replaced it with a NAPA part that did not fix the issue).

Unfortunately, the IAC appears to have fixed the idle problem that presented itself when I turned the A/C on and off, and when I put the transmission in park or neutral from drive or reverse (it would almost die when I turned the A/C off, or put the car from drive into neutral or park). However, that could also just be because I unhooked the battery to reset things, and it has not yet "re-learned" that part of the problem. Time will tell in that regard, I suppose.

On the way to work today, it died once at idle, and twice at freeway speed (60-70). @#$(&#@$ !!!!

However, it sure seems that what is left is an ignition problem, rather than a fuel problem, so for that reason (and because I have already replaced the IAC twice *LOL*) I will probably focus now on the ignition system.

I have replaced only the IAC and the CPS so far. Next I will probably replace the Camshaft position sensor and the coil, and see where that gets me.

When the engine fails, it falters and misfires before it dies, and in some cases (all cases today) it went on misfiring and coughing until I actually killed the ignition switch....though I didn't wait that long after it started to kill the switch, since my experience has shown that the longer I let it sputter, the longer it takes to restart again.

Based on my experience with other, non-fuel-injection/computer controlled cars, it really feels like an ignition/timing issue. For that reason I'll probably replace the cam position sensor first, then the coil.

If neither fixes the issue, then I need to read up in my Jeep OEM repair manuals to try to figure out if a bad MAP sensor could cause this issue. I have seen in many other posts that it was the MAP sensor that caused this kind of thing, but then again, I have found threads in which every single component of the sensor system and the ignition system has been blamed for identical issues at some point or another.

I really am tempted to take the jeep into a local repair shop and have them put it on a reader for me and tell me what they think it is. I may do that before replacing anything else...but I am just afraid they will end up trying to fix by part swap as I am doing anyway.

Every time I swap a component I get so jazzed...sure that I have fixed it this time...and every time so far my hopes are dashed upon the jagged rocks of despair again. *LOL*

Oh well...either it will get fixed or it will get traded for a new Ford pickup truck quicker than I would like. *sigh*

i was at the jeep dealership yesterday talking to the parts pro about my problem, and he said the ignition coil might be the problrm for mine, i just need to look at the gauge of the wire, he told me that he had a 96 jeep exactly the same as mine with the same problem. the jeep had an aftermarket ignition coil, and the connections didnt match up perfectly.

he said the male connectors were way too small for the female, so there was play in the line and it didnt connect all the way around.

So im gonna check into that one.

Nope, I have not considered replacing the PCM as of yet. That seems like a last resort to me. I did replace the IAC motor again this morning, with a MOPAR part (had already replaced it with a NAPA part that did not fix the issue).

Unfortunately, the IAC appears to have fixed the idle problem that presented itself when I turned the A/C on and off, and when I put the transmission in park or neutral from drive or reverse (it would almost die when I turned the A/C off, or put the car from drive into neutral or park). However, that could also just be because I unhooked the battery to reset things, and it has not yet "re-learned" that part of the problem. Time will tell in that regard, I suppose.

On the way to work today, it died once at idle, and twice at freeway speed (60-70). @#$(&#@$ !!!!

However, it sure seems that what is left is an ignition problem, rather than a fuel problem, so for that reason (and because I have already replaced the IAC twice *LOL*) I will probably focus now on the ignition system.

I have replaced only the IAC and the CPS so far. Next I will probably replace the Camshaft position sensor and the coil, and see where that gets me.

When the engine fails, it falters and misfires before it dies, and in some cases (all cases today) it went on misfiring and coughing until I actually killed the ignition switch....though I didn't wait that long after it started to kill the switch, since my experience has shown that the longer I let it sputter, the longer it takes to restart again.

Based on my experience with other, non-fuel-injection/computer controlled cars, it really feels like an ignition/timing issue. For that reason I'll probably replace the cam position sensor first, then the coil.

If neither fixes the issue, then I need to read up in my Jeep OEM repair manuals to try to figure out if a bad MAP sensor could cause this issue. I have seen in many other posts that it was the MAP sensor that caused this kind of thing, but then again, I have found threads in which every single component of the sensor system and the ignition system has been blamed for identical issues at some point or another.

I really am tempted to take the jeep into a local repair shop and have them put it on a reader for me and tell me what they think it is. I may do that before replacing anything else...but I am just afraid they will end up trying to fix by part swap as I am doing anyway.

Every time I swap a component I get so jazzed...sure that I have fixed it this time...and every time so far my hopes are dashed upon the jagged rocks of despair again. *LOL*

Oh well...either it will get fixed or it will get traded for a new Ford pickup truck quicker than I would like. *sigh*You know that sooner or later a fix is on the way----but how long can a person wait??? I still have not had a total sputtering/stall/die situation in the last week, but at idle and sometimes at speed I can hear it missing some. This weekend I plan on taking the trottlebody out and cleaning all the ports, and replacing the gasket. Also plan on stripping away the plastic sheath to all the wiring going from the cps to pcm, the coil to pcm, and map to pcm and check for shorts and continuity issues.
If I find anything will let you know. As for the replacing of the camshaft sensor and coil--personally don't think these items will help--at least they did'nt help for me. I replaced the coil 3 times, the final time with a Mopar-no difference: and I replaced the camshaft sensor 2 times and then the whole distributor, since the rotor shaft had some play in it---still no difference.
I read a thread on page 70 where this guy had exactly the same issues we were having and after throwing everything into it finally took it to the dealer to find out that once the pcm got warmed up (15-25 min.) it started dropping out and causing the misfire. In his case the pcm was definitely his fix.
I also want the pcm to be my last resort, and will go through all the other ideas before dropping the bucks. Even if I have to replace the pcm it still is equivalent to just a one month car payment! Not bad---but if it doesn't fix it that will put my wife on a "new car binge"push--to which I may have to concede! Let's push for a fix here!!!!

I think I may just go the PCM route...gotta think on it while I'm off for four days in Las Vegas ;)

I did lots of reading online today, and seems like many, many folks have replaced pretty much the whole ignition system and had it turn out to be the PCM. I'll check all my connectors first, of course, but am really leaning toward the PCM after today's reading.

Sheesh. I love the simplicity of my '67 Cougar. Something goes wrong, you fix it. Much more obvious to figure out what the problems are. Thank Gawd I have that car too, otherwise I'd be walking 25 miles each way to work before long *LOL*

Good luck y'all, over the next 4 days...I'm off to the National Finals Rodeo in Las Vegas, baybeeeee!!!

Well, the #@$(*#@$&@#*(& died on me TWICE on my way home from work tonight.

This time it started bucking when cold/warm (as it did this morning) and did its dieseling (sounded just like detonation and pinging, actually) almost from the get-go up to about a half hour into the drive. Then miraculously, drove like a champ the rest of the way home (another 45 minutes to an hour).

The worse it gets, the more it seems to misbehave early on in the drive, then stabliize after about a half hour.

The new IAC though, seems to have fixed the issue with stumbling of the engine speed when I cycle the A/C off and on...so at least there's that. Now it's just the random timing deaths. Idle seems fine now, so I think that NAPA part (the IAC before the MOPAR one) was a piece of crap.

So now it's just the stumble and it dies.

Coming from an electronics background (computer programming and interface design) it seems like it could be the PCM or other electronics. I thought perhaps a connector or wire is loose, but why then would it settle down after a half hour? So I'm thinking PCM. However, every time I think about it, I can rationalize one component or another, so I no longer trust my troubleshooting ability much. *LOL*

I know that in PC's and servers, if there is a crack on a solder joint or in a circuit board, that sometimes heat expands the joint/component enough that the short or circuit break goes away. Maybe that's the deal. Maybe that's why it misbehaves when cold, then settles down after a half hour? I dunno. I think I am now looking for ways to rationalize why I think it might be a particular component.

I'd take it to a shop or the dealer if I had even one iota of confidence that they could tell me something other than to try to fix the issue by random part replacement, and Lord knows I can do (and have been doing) that myself.

Sheesh. I did so much searching online today, and so many people have replaced every part in the ignition system only to have the trouble continue until they replaced the PCM, that I am thinking I may just bite the bullet and order a new/remanufactured one upon my return from Las Vegas.

How completely frustrating and depressing this whole thing is. I am a good mechanic, dammit!!!!! I can ALWAYS figure out what is wrong with cars. This really chaps my drawers and frosts my grandma's preserves.

If I could afford the payments right now, I would dump this sorry ass JGC and go buy the truck I wanted in the first place (before my wife convinced me that we needed the extra seats for the kids, who are now all driving thier own cars!!!). The only thing is that I fear I would bump into a similar issue with the new truck at some point *LOL*

Damn...this thread is taking on the feel or a blog! *LOL*

Oh well, I'm done thinking about it for the next 4 days.

Wish me luck at the Blackjack table!!!

StudMuffin, OUT!!!

Well, the #@$(*#@$&@#*(& died on me TWICE on my way home from work tonight.

This time it started bucking when cold/warm (as it did this morning) and did its dieseling (sounded just like detonation and pinging, actually) almost from the get-go up to about a half hour into the drive. Then miraculously, drove like a champ the rest of the way home (another 45 minutes to an hour).

The worse it gets, the more it seems to misbehave early on in the drive, then stabliize after about a half hour.

The new IAC though, seems to have fixed the issue with stumbling of the engine speed when I cycle the A/C off and on...so at least there's that. Now it's just the random timing deaths. Idle seems fine now, so I think that NAPA part (the IAC before the MOPAR one) was a piece of crap.
Coming from an electronics background (computer programming and interface design) it seems like it could be the PCM or other electronics. I thought perhaps a connector or wire is loose, but why then would it settle down after a half hour? So I'm thinking PCM. However, every time I think about it, I can rationalize one component or another, so I no longer trust my troubleshooting ability much. *LOL*

I know that in PC's and servers, if there is a crack on a solder joint or in a circuit board, that sometimes heat expands the joint/component enough that the short or circuit break goes away. Maybe that's the deal. Maybe that's why it misbehaves when cold, then settles down after a half hour? I dunno. I think I am now looking for ways to rationalize why I think it might be a particular component.

I'd take it to a shop or the dealer if I had even one iota of confidence that they could tell me something other than to try to fix the issue by random part replacement, and Lord knows I can do (and have been doing) that myself.

Sheesh. I did so much searching online today, and so many people have replaced every part in the ignition system only to have the trouble continue until they replaced the PCM, that I am thinking I may just bite the bullet and order a new/remanufactured one upon my return from Las Vegas.

How completely frustrating and depressing this whole thing is. I am a good mechanic, dammit!!!!! I can ALWAYS figure out what is wrong with cars. This really chaps my drawers and frosts my grandma's preserves.

If I could afford the payments right now, I would dump this sorry ass JGC and go buy the truck I wanted in the first place (before my wife convinced me that we needed the extra seats for the kids, who are now all driving thier own cars!!!). The only thing is that I fear I would bump into a similar issue with the new truck at some point *LOL*

Damn...this thread is taking on the feel or a blog! *LOL*

Oh well, I'm done thinking about it for the next 4 days.

Wish me luck at the Blackjack table!!!

StudMuffin, OUT!!! Hi again! Without a lot of hoopalla and going around in circles....I finally found a fix for my jeep!!!! Really!!! I was getting so deperate and after trying just about everything I came across this article which was written by a mechanic/ instructor who has been teaching for 25 years. Rather than me tell you, just go to this site and read for yourself----it is definetely worth the read if you are experiencing misfire/stalling problems. Click on this link http://www.motorage.com/motorage/data/articlestandard/motorage/292005/169830/article.pdf
This site will explain a simple alignment of the camshaft syncronizer for perfect timing. Apparently after 235K miles on my jeep the timing chain has stretched and I needed to reset the alignment of the pulse ring in relation to the new distributor I installed. Once I did this, my jeep has been running like a champ!!!!! I am really thankful for this info. because I was just about to buy a PCM for $600 ---that I really didn't need. Praise the Lord!

Outstanding!!! That makes alot of sense based on what I have seen with mine. Dropping a few cylinders could certainly explain a bit of the increase mileage I am seeing since the problems started...hey, maybe I've been driving a 2-cylinder to work for the past few months! *LOL*

Couple questions though...I will probably do this tomorrow night, and so probably will get the answers from my shop manual or what I see, but here are some questions for ya.

How do you find TDC in these engines? Just take out the spark plug and crank it a bit until you hear the whoose of the compression stroke? Put a screwdriver in the plug hole and watch for the top? Just curious, since on my older engines I have a timing mark on the crank to look for.

Also, I have only seen pictures that I did not look really close at, but how do you adjust the distributor (camshaft) sensor? Are the holes elongated to allow for adjustment?

Seems also that since the TDC location is kinda non-precise, that aligning two toothpicks would be subject to some misalignment also...was the distance your two "holes/toothpicks" were off significant enough that you felt good about making that adjustment? I mean, we're talking about basic timing.

OK, didn't mean to give the third degree, just want to make sure of what I am up against...alot of what he says makes sense....would be cool to get my jeep fixed replacing all the random sensors...and before I head to Carmax this weekend to look at that black F-100 Harley Davidson LE truck I have been eying lately... ;)

OK, did some further research, but need one more bit of help...Speckster...

Looking at my repair manual, I finally figured out that there is a timing mark on this engine *LOL* (hey, I don't ever have to set the timing, so how was I to know!?!?) so I can find TDC just fine. AND, I figured out from a picture I had missed in the article where the toothpick goes.

Now, nowhere could I find info about how the camshaft synchronizer ring is moved? In the picture I don't see a bolt or screws anywhere, and surely it is not just moveable by hand? Again, I'll probably see something when I get the guts out of the distributor, but just to help with the warm fuzzies before I tear into it tonight....

Thanks again, I'm keeping my fingers crossed that your thang is still fixed, and that mine will be by this evening!

OK, did some further research, but need one more bit of help...Speckster...

Looking at my repair manual, I finally figured out that there is a timing mark on this engine *LOL* (hey, I don't ever have to set the timing, so how was I to know!?!?) so I can find TDC just fine. AND, I figured out from a picture I had missed in the article where the toothpick goes.

Now, nowhere could I find info about how the camshaft synchronizer ring is moved? In the picture I don't see a bolt or screws anywhere, and surely it is not just moveable by hand? Again, I'll probably see something when I get the guts out of the distributor, but just to help with the warm fuzzies before I tear into it tonight....

Thanks again, I'm keeping my fingers crossed that your thang is still fixed, and that mine will be by this evening!Hi again! Good, I'm glad you found a book, because it should have pics of the dist. and how to line everything up. I have a Haynes manual. Anyway, your approach to TDC is good (like the old guys used to do), but be sure that as you are turning the crankshaft bolt clockwise to bring the flywheel to the "0" mark, that you don't go past it and then try going back counterclockwise to hit the mark. TYhe reason I say this is because if there is any paly in the timming chain it can cause a false read of true TDC. Actually, I took the dist. cover off,as well as the center coil plug, took out spark plug #1 and put a comp. gauge on cylinder #1 and used the key to engage the starter in small increments until the rotor was pointing to the 4 o'clock postition and compression started going up. Then I took a breaker bar with a 3/4 inch socket and turned the flywheel bolt clockwise very slowly and kept checking the notch until it lined up with the "0" mark on the timing marker. At that point I took a 3/16 drill bit and wrapped some tape around the bit 1.5 inches away from the bottom, and inserted it through the plastic ring in the distributor and then down through the hole in the dist housing. There are two holes in the plastic, one for the 4cyl, and one for the 6cyl.--you want to use the hole on the leftmost side--the book should have a picture. Once everything is lined up, then insert the dist down into the hole and be sure the rotor is facing the 5'oclock position when fully bottomed out. There is no adjustment on the camshaft sensor--it just fits into the top of the dist housing. Hope this helps!

Oh, OK, that's interesting...I saw that in the book, I thought I read the article to be talking about inserting a toothpick into the actual sensor, rather than taking out and lining up the distributor itself... Hmmmm...I'll check it out regardless.

Well shazbat!

I got to the garage this morning and got to work, and (a) found that the distributor has an oil seal that they say can't be reused, so I need to get that before I go to taking the distributor out, and (b) can't figure out how the heck to see the TDC marks on the timing chain housing!!!!

How the heck do you see them? Looks like unless someone can provide the secret, I'll need to at least take the fan off, and most likely the fan shroud also. Unfortunately, I didn't leave myself enough time to do all that work too. I need to go to a birthday party this afternoon. Dang!

Have I correctly outlined what I will need to do to see the timing marks? Sheesh. I guess they hide them behind the serpentine belt and the power steering pump and the belt adjusting bracket since you really don't have to see them except when you are replacing the distributor, but good lord! Since when do manufacturers hide the timing marks so carefully.

It's always something, and I just wanted to whine a bit since I really thought it would be only an hour or so job...OH well...perhaps next weekend.

If I missed a secret method for seeing the marks, please enlighten me. *sigh*

Well shazbat!

I got to the garage this morning and got to work, and (a) found that the distributor has an oil seal that they say can't be reused, so I need to get that before I go to taking the distributor out, and (b) can't figure out how the heck to see the TDC marks on the timing chain housing!!!!

How the heck do you see them? Looks like unless someone can provide the secret, I'll need to at least take the fan off, and most likely the fan shroud also. Unfortunately, I didn't leave myself enough time to do all that work too. I need to go to a birthday party this afternoon. Dang!

Have I correctly outlined what I will need to do to see the timing marks? Sheesh. I guess they hide them behind the serpentine belt and the power steering pump and the belt adjusting bracket since you really don't have to see them except when you are replacing the distributor, but good lord! Since when do manufacturers hide the timing marks so carefully.

It's always something, and I just wanted to whine a bit since I really thought it would be only an hour or so job...OH well...perhaps next weekend.

If I missed a secret method for seeing the marks, please enlighten me. *sigh*Hey! Yeh, this problem seems to always present itself at the worst times!! Anyway, the timing marks are really not that hard to locate. Take a small flashlight (like a mini-mag lite), and place it behind the fan blades on the upper right side. Then direct the light beam down toward the crank pulley at about the 1 o'clock position to the rear of the pulley just behind the pulley. You should be able to see the marks, if not, take a can of carb cleaner with the 5inch red tube extension and squirt the area clean of old oil debrie. Then to locate the timing mark on the crank, get underneath the the radiator area and pull off the plastic shroud nearest the front radiator(held on by 4 plastic grommnets). That gives you perfect access to find the groove in the pulley and also mark it with some white chalk to see it better. Also, I left all the other spark plugs in and just put a 2' breaker bar with a 3/4 socket on the crank pulley bolt to turn the engine for alignment proceedures. Good luck! Oh, by the way, how many miles do you have on it again, and did you have an injector cleaning done proffessionally? Just thot to ask because injectors also cause stalling issues--the more I read about this problem. Get back with me---Speck

Not necessarily the approved fix, but I no longer have an idle issue in my '97 GCL...

Got a good price on a 2002 Ford F-150 King Ranch edition truck, and jumped on it over the weekend. Got $2,000 for the '97 on trade-in.

Got my money's worth out of that jeep, I suppose!

Since my last post, I re-set the basic timing in the jeep - that made absoluetly NO difference in my case. I also had bought a new coil, but had not put it on yet. That will go back to the parts counter tonight.

Best of luck to all y'all still struggling with the issue. Sorry to bail on ya, but I have always wanted my truck, and this edition is icing on the cake!

StudMuffin, Out!