Park is fine; in gear,runs terrible.

[sharter]

Can someone please help? My '98 Ram runs great when reving the engine in park but when in gear it runs terrible. While going down the road it is erratic. I get it home and put it in park and it runs fine. Could it be a transmission sensor? I can put it in drive and hold the brake and it is erratic and unstable. It has high miles. 5.9 engine, 4X4.

How about it fredjacksonsan,any clues?

Thanks for replys. It helps!

[Blylock]

what do you mean by erratic. it it skipping, backfiring, hesitating?

[sharter]

Well it kind of sounds as if it may be skipping terribly.
Has new plugs,cap,rotor button,O2 sensors. What else? Maybe add new wires? I don't know what it could be.
Everyone is saying that the cat is bad.
Then this morning it seemed to be doing it in park.

Thanks.

[sharter]

Originally Posted by sharter

Well it kind of sounds as if it may be skipping terribly.
Has new plugs,cap,rotor button,O2 sensors. What else? Maybe add new wires? I don't know what it could be.
Everyone is saying that the cat is bad.
Then this morning it seemed to be doing it in park.

Thanks.

Oops! I failed to mention it has a new coil also.

[Blylock]

usually a bad cat it would feel like your hitting the gas but going nowhere. when mine went bad, it didnt skip, it just plain wouldnt go when i hit the gas. still sounds like to me you have an o2 sensor problem. just because they are new, dont mean they arent bad. best bet is to take it to a monro muffler or some place similar, they will put a scanner on it and see whats messing up, for free. also pull your plugs and see if they are black, oiled or anything. if they are new, they should all be relatively clean, or a light brownish.

heres a few things to do if you want to troubleshoot yourself

as mentioned above, pull your plugs, make sure the gap is right and see for unusual conditions. light brown is good, black is bad.

have someone keep the motor about 2500 rpms, crawl under the truck, if the cat is bad, it will usually start to glow red within 10 minutes

take your TPS and IAC off your throttle body, clean them good and replace. look inside the throttle bores and see if its black with crap. get some carb cleaner and spray the hell out of it, use something soft to get inside the bores and the throttle plates. also look for oil on the bottom of the intake while your in there. when you get it all together, start the truck with your air cleaner off, get some seafoam or carb cleaner from the auto store, hold the throttle to about 3k and slowly dump it in the throttle body bores

check all vacuum lines and listen for leaks, or ones that may be off. this can reak havok

if you decide to do any of this, post your findings. the look of your plugs is a good sign of whats going on.

if they are dry black, your cat might be bad, or your o2 sensors are telling the truck to run rich

light brown deposits, like sandy chunks is a sign of running lean, or overheating

wet black is usually oil burning.

blue exhaust smoke is usually oil, thick white is coolant, black is too much gas (running rich)

[sharter]

Well today it was running really bad & the check engine light came on. Well I took it to Advance Auto. They scanned the computer. It came up a code for the # 4 cylinder misfiring. So I bought new wires & installed. I've replaced everything else but the wires. It ran real good. So I took a road test. It ran better than before but I think I have another problem as when I step on the gas (floor board it) it jerks and hesitates. As I said the wires made a big difference. I have to clear another problem as I think I had multiple problems at once. I'm going to try the things that you suggested Blylock. There is no monro shop here but maybe some other muffler shop can help. Thanks for the tips! You are a really helpful!

[Blylock]

Originally Posted by sharter

Well today it was running really bad & the check engine light came on. Well I took it to Advance Auto. They scanned the computer. It came up a code for the # 4 cylinder misfiring. So I bought new wires & installed. I've replaced everything else but the wires. It ran real good. So I took a road test. It ran better than before but I think I have another problem as when I step on the gas (floor board it) it jerks and hesitates. As I said the wires made a big difference. I have to clear another problem as I think I had multiple problems at once. I'm going to try the things that you suggested Blylock. There is no monro shop here but maybe some other muffler shop can help. Thanks for the tips! You are a really helpful!

how did your plugs look?

[theFREAKnasty82]

have you had any tranny work? An imbalanced torque converter can cause similar issues.

[sharter]

Originally Posted by theFREAKnasty82

have you had any tranny work? An imbalanced torque converter can cause similar issues.

Just to udate the issue. No tranny work has been done. Took it to a garage today and after checking seveal things like compression and spark to # 4 cylinder the mechanic took the plug out of # 4 and replaced it. Afterwards it ran great! I cost me $40 bucks for work. Only if I had tried that myself. These were new plugs installed 4 months ago.

Thanks for all replys from everyone.

[Blylock]

Originally Posted by sharter

Just to udate the issue. No tranny work has been done. Took it to a garage today and after checking seveal things like compression and spark to # 4 cylinder the mechanic took the plug out of # 4 and replaced it. Afterwards it ran great! I cost me $40 bucks for work. Only if I had tried that myself. These were new plugs installed 4 months ago.

Thanks for all replys from everyone.

if your getting 4 months out of plugs, you got some problems

[sharter]

Like what kind of problems? This was only one plug that went bad and it was not burnt. It was just not firing through the plug. The guy ohmed it at Auto Zone and there was no continuity through it.

[fredjacksonsan]

After replacing the bad plug(s), how does it run?

[sharter]

It runs great! I could not believe the effects of what one bad plug would do. This plug had no contiuity through it when checked with an ohm meter. So it was not firing.

[scrankshaw]

Rough idle under load, not in park or neutral, also caused by a faulty EGR system (valve & sensor) . Had the same problem with my 95 Ram 5.9L which took weeks to troubleshoot.