Surging RPM Problem At Freeway Speeds - Help Diagnosing

Hey all,

This is an annoying issue I've been dealing with for quite a while, but this weekend it got bad enough that I'm to the point that I really want it solve whatever it is.
The problem is strange and hard to describe so I'll do my best. It only ever happens when I'm going freeway speeds. Usually, I'll be driving along and for whatever reason I'll need to push on the gas to the point that it increases the RPM's, but not quite enough to make the transmission shift down (auto trans.). If I'm cruising along at 65-70, the RPM's are just barely over 2K. If I push on the gas and get it up around 2.5K, then the RPM's start surging up and down in an oscillating pattern- going up a few 100 RPM's and then down again quickly and the engine sounds like it's bogging down or flooding or something.
Now if I go back to just cruising along at 65-70; if I give it enough gas to shift down, it does so smoothly, I get great acceleration, and there's no sign of any problem. It's just when I stay within the gear I'm already in and give it more gas-but not pinning it.
This never happens at any other time - it idles very smooth and I have no clue what this could be. I'm sorry if this is not the most coherent explanation, but I just can't think of how else to explain it. :headshake

If anyone wants to take a stab or has any ideas of things for me to check, I would really appreciate it!...

Almost sounds to me like your TCC is not locking up correctly. Do you have a scanner?

Almost sounds to me like your TCC is not locking up correctly. Do you have a scanner?

I have a code reader, but that's it. What's a TCC?

Im with troy, sounds like it could be TCC problems. TCC = Torque Convertor Clutch btw. Mine does the same thing on my impala, but my trans is a mess right now period. :lol2:

TCC Indicision definatly.

One question, do you have any modifications to the throttle body area? How is your MAF screen? (still in place?)

Oh great. :banghead:

What kind of a fix/cost would be required if that turned out to be the case?

I haven't made any mods to the throttle body and the MAF screen is in place. The closest thing to a mod in that area would have to be my cold air (kinda). The cone filter is still under the hood, but I have a lead pipe that goes behind the driver's side fog light. I used to have a true cold air, but I think the pipes were too small and the engine seemed like it wasn't getting air fast enough. So when I shortened the distance between the MAF and the air filter, that seemed to fix it.

I'm taking the car in tomorrow so this info really helps me. Is there anything else this could be? How would a shop go about finding out if this was a TCC issue for sure?

Remove the MAF and clean it with some MAF sensor cleaner

Ok, I'll give that a try. Is there actually a MAF Sensor cleaner or can I just use carb cleaner?

I've been doing some more searching on here and am surprised that others have experienced the exact same symptoms. It makes me laugh because I was almost quoting others verbatim when I thought there was no way I was making sense. The only down side is that I didn't see a common solution to these issues.

If cleaning the MAF doesn't yield anything, here is a list of things I've gathered that may lead to a solution:



Tranny Code Scan
TPS Sensor check
TCC Solenoid check
Excess valve body wear in the TCC valve area?
Worn or shrunken teflon seals on the input shaft?
A bad o-ring on the input shaft that seals in the torque converter?
A faulty torque converter clutch?
A bad pressure control solenoid?
Worn out sleeve in the channel plate that supports the input shaft?
Check pressure relief valve in the channel plate for debris



Verify proper operation as commanded by the pcm is with a scan tool by viewing TCC slippage rpm, TCC duty cycle, EPC data, and checking any codes and making sure the engine is running properly and a misfire is not a false sense of a torque converter problem or shudder.


Possible Solutions:



New or reman / repaired valve body?
New EPC solenoid?
New TPS
New TCC Solenoid



Anything anyone wants to add to the list?? :runaround:

Do not use carb cleaner on a MAF, it will ruin it. MAF cleaner leaves no chemical residue, carb cleaner does.

On your surging issue, it's most likely a TCC valve or TCC control circuit/wiring issue. The TCC controls torque converter lock-up, and is a common issue in these transaxles and causes your exact symptoms when they start to go.

My car was doing it after I switched from my stock t-body to a ported zzp stage 1 t-body with no maf screen. As soon as I put the maf screen back in there, problem solved.

I almost wonder if the cone filter oil isn't gumming up your MAF sensor.

Like Rich said, you could also ohm check the TPS.

Well I'm running it in to the shop right now because I won't have time later. Thank you so much for the help guys and I'll report back later with what they say! Stay tuned...

sorry to post on this topic. IF it is his TCC how much would something like that cost a transmisson shop to fix.

sorry to post on this topic. IF it is his TCC how much would something like that cost a transmisson shop to fix.

N/P. I'm wondering the same thing.

New TCC = rebuild.
Solenoid = $500
Wire = $300

Holy :swear:

Please be the TPS, please be the TPS, please be the TPS......:worshippy

I should be hearing back any minute as to the verdict...

So the shop just called...

He said that he hooked up the scanner and there weren't any codes stored in the transmission. He said he watched the shifting and it seemed to shift at each point when it was supposed to.
He went on to say that for a little bog to happen is normal because when the torque converter locks (overdrive?) it's to increase efficiency at high speeds. He said he took it for a couple drives and got it to bog down, but not surge like I was explaining. He said with no codes and everything looking good on the scanner he wasn't too sure what the issue was. He said a little bog is normal, but surging isn't so he referred me to a transmission shop who is going to be more specialized. I appreciated him not trying to blindly guess as to the problem, but now I'm not sure where to go with it (I'm going to call the tranny guy in a minute). In the meantime, is there anything else specific to check? They said the checked the TPS and it checked out okay.


....Just got off the phone with the tranny guy and he said he really wouldn't be able to know until he could actually drive it. So I gotta go grab the car and bring it over to him. He said he had a case where it was similar to what I was describing and it ended up being an issue with the engine- not the transmission. The customer took it to an engine place and didn't want to fork out the money to correct the supposed engine problem, so they never found out for 100% certain what the fix was.

:shakehead

i had the same problem with my GT...and just fixed it a couple weeks ago. mine was doing exactly as you describe. i thought for sure it was a TCC. well...over time it get worse and worse...then FINALLY the SES light went on a couple weeks ago. random multiple misfire...and bank 1 sensor 1 o2 sensor. replaced the o2 sensor, and found a bad wire in the back that was arching out on the rear exhaust minifold.

car runs good as new now. i guess the point is...before jumping into the TCC check everything else.

i guess the point is...before jumping into the TCC check everything else.

I think that's excellent advise and here's why...:thumbsup:

I called my shop back and spoke to the the mechanic that was actually the one trying to diagnose the issue. He was trying to explain to me why the car seems like it bogs down a little when the torque converter is locked in and I could tell he really wasn't understanding what was going on, so I offered to take him for a spin and show him myself. I raced down there from work and they actually had a different mechanic go with me who was apparently the most knowledgeable about transmissions. He plugged in this huge scanner that was about as big as my steering wheel and monitored the readings as I drove. Of course my car decided to behave for the most part, but I was able to get it to act up a little bit as we were driving up a few hills. He said that he did see some slippage and he said that what caught his attention the most was engine load at the shift points. I can't remember exactly how he put it, but he said that the engine didn't think it was working as hard (or as little, I can't remember) as it really was and he believed it was throwing the shifting off a little bit. We got to talking more and long(er) story short, we think it actually might be caused by my cold air (of sorts). As I thought about it, I did realize that when I first took out my stock air box was when I first started noticing this issue. Back then I thought that my cheap cone filter was probably to blame and was restricting air to the engine (I had totally forgotten about that whole thing, too). Obviously it's just a hunch, but when he explained it to me, all the pieces fit. So the idea now is to put my stock air box back in and see if the problem goes away. If it does, then I know what the issue is. Whether it turns out to be this or not, it's an easy, costless experiment to find out for sure.
He said that if this does turn out to be the issue then he said I'm fine leaving my cold air on as long as I don't let the engine bog down too bad in these scenarios because it will heat up the tranny and cause excess wear. He said when it starts to do that, just give it enough gas to shift down and problem solved. The other alternative he offered would be to get a programmer and adjust the computer to handle the cold air. I like the programmer option, but we'll see how money fairs the next few months. After the holidays maybe. I want to get a smaller pulley too.

So I'll put the stock air box in tomorrow night and we'll see what happens. I'll be watching the RPM needle like a hawk.

Oh! And thanks to him, I finally found out exactly why you don't want to flush a transmission after so many miles and what actually literally physically takes place when you do! I'm a true no-flush believer (not that I wasn't before - I just didn't understand why)!

did you just take a cone filter and throw it on the end of your rubber intake tube? if you did...IMO get rid of it. reason being is that setup actually takes in warmer air than your stock airbox does.

if you want a true CAI then get the one that goes into the fender wall.

It's been my experience that a CAI, except on highly modded vehicles, is a waste of money.

Not only are the real world gains of a CAI minimal if not non-existent, but the filters they use don't do a very good job of keeping dirt out of your engine.

Basically, what I'm saying is that $$ spent for no gians + more dirt in your engine = a bad investment.

Let us know what you find when you get your factory airbox re-installed.

did you just take a cone filter and throw it on the end of your rubber intake tube?

:lol: Yeah, I'm not sure that route would yield any benefit, myself. I got a CAI pipe and hooked that to the rubber hose and put the cone filter on the other end, right up next to that little hole in the fender. The end of the cone actually sits in that hole a little bit. Then I put a lead pipe that connects to the end of the cone filter down to behind the driver's-side fog light so that I actually get somewhat of a cold/ram air affect, however small it may be. Here's a picture I already had for something else, but you can see the pipe. My cone filter is actually just right outside the picture on the right.

richtazz, I can't honestly say that I noticed any real difference in performance when I put that thing on. Do you all have stock air boxes on your Prix's? Tim? Bob? You too?

My car is not modded in any way, and I still have the factory air box.

The factory air box can flow about 800 cfm. In order for a 3800 to exceed 800 CFM, a non supercharged VIN-K would have to be turning about 8500-9000 rpm or a supercharged VIN-1 one would need to be running a ton of boost. So all the theoretical gains of a CAI are a moot point (other than in highly modded cars) seeing as how the stock air box can flow way more air than the engine can ingest, and a quailty paper filter can trap way more dirt than a reuseable gauze style. Most people that install a CAI just think they're going faster because the intake makes more noise (kinda like old school guys that flipped their air cleaner lids upside down so you could hear the engine roar as you stomped the gas pedal).

Ha, ha, ha, well duh! Louder car = faster car! Everyone knows that! :naughty:

Thanks for that stats, that's actually really interesting. So here's the question- assuming everything you said is 100% accurate (I'm not meaning to suggest it's not) and assuming that my little issue here is solely due to the CAI and the alleged change in air volume, what can we deduce from that?

Could we say that the cold air is forcing the engine to consume more air that it’s supposed to and that’s why I’m having the shifting problem?

Or could we say that the cold air is pushing more air past the MAF than is actually being consumed by the engine and that’s the reason for the communication disconnect between the engine load and the TCC disengagement?

I completely agree with the concept that presenting air to the engine faster than it can consume will only lead to issues.

Does your CAI have a provision for the IAT (Intake Air Temp) sensor?

If not, then the PCM isn't compensating for the change in air density due to ambient temps.

Also, when you installed the CAI, did you remove the honeycomb MAF screen?

If you did, the resultant turbulence can mess up the air flow signal picked up by the MAF, causing all sorts of driveability issues.

Does your CAI have a provision for the IAT (Intake Air Temp) sensor?

When you say "provision," do you mean does it have an IAT sensor installed in the CAI apparatus itself? If so, then no. Could that potentially solve my problem? How would I go about doing that? In the picture I posted a few posts ago, you can see a sensor on the rubber tube at the top. Isn't that the IAT sensor?

Also, when you installed the CAI, did you remove the honeycomb MAF screen?

I didn't touch the MAF when I installed the CIA (yes, screen is still there).

Ok, sorry I didn't notice the pic.

Yes that sensor in the rubber tube is what I was referring to.

Ok, so let me make sure I got this straight. What you're saying is that the engine will only take a certain volume of air and that the stock air box provides the full amount needed. So even if I were to put the stock air box back in and say put a K&N filter (not cone, but brand replacement) in it, it really wouldn't do any difference because the engine is already taking its max air with a regular paper filter? The only difference is that with a CAI or a K&N filter (square kind) I'm increasing air flow past the MAF, but the engine is burning the same volume of air in all three scenarios? :uhoh:

Also, if I'm putting 2 & 2 together, getting a programmer really wouldn't do anything more than just telling the PCM that the MAF is really seeing more air volume than it normally would if it were stock, but it wouldn't actually allow more air to be consumed by the engine?

:runaround:

Ok, so let me make sure I got this straight. What you're saying is that the engine will only take a certain volume of air and that the stock air box provides the full amount needed. So even if I were to put the stock air box back in and say put a K&N filter (not cone, but brand replacement) in it, it really wouldn't do any difference because the engine is already taking its max air with a regular paper filter?

This part of your statement is exactly what I mean, minus the K & N stock replacement filter because again, there is no reason to use one and plenty of reasons why you shouldn't use one. By the time you buy the spendy K&N and the oil and cleaning kit for it, you'll spend more money and time dealing with keeping it clean and oiled than a regular quality drop in filter will cost to replace over the life of the K&N. Not to mention the risk of excess oil getting sucked out of the K&N and into your MAF sensor ruining it and the dirt that escapes by one getting in your engine.

The only difference is that with a CAI or a K&N filter (square kind) I'm increasing air flow past the MAF, but the engine is burning the same volume of air in all three scenarios? :uhoh:

Using a cheap CAI that doesn't actually draw air from the cowl will actually decrease performance due to the fact that underhood air is hotter than ambient air, it has nothing to do with increasing maximum air flow potential
ahead of the MAF. Hotter air is less dense, so it will cause the PCM to adjust fuel delivery to compensate. If your CAI went into the fenderwell and the incoming air drawn through it was isolated from underhood heat, then it may not be related to your issues, but you stated earlier that it was just a cone filter that sort of tucked into the hole in the fender...not good.


Also, if I'm putting 2 & 2 together, getting a programmer really wouldn't do anything more than just telling the PCM that the MAF is really seeing more air volume than it normally would if it were stock, but it wouldn't actually allow more air to be consumed by the engine?

:runaround:

Unless you have other mods (ex. smaller S/C pulley, headers, hi-flow cat, etc...) a programmer wouldn't change anything. I think the CAI you have is a big part of your issues.

I hope this clarified things for you.

All very good info, richtazz; I really appreciate it! I was starting to get off on a mod tangent a little bit there so thanks for humoring me. :rolleyes: I think I'll start another thread for my mod questions.

Back to my issue - the shop threw on a new hub for me and was just about to wrap up with the valve cover gaskets, when they noticed a HOLE in the rear valve cover itself!!! They weren't sure how that would happen, but he thinks bad motor mounts might have allowed the bolt on the alternator to hit it somehow. :confused: Anyway, where it's plastic, they're going to weld some plastic in that hole and say it should be good as new! Good thing because no GM dealership in the valley had one and it was three days to get one in!

I'm picking up my old air box from storage tonight and will put it in tomorrow night after I pick up the car. With new valve cover gaskets, a repaired valve cover, and it's old air box I bet the car will be feeling vibrant and youthful again. :lol:

Weird! But how could an alternator bolt hit the valve cover?

I have a stock air box with a paper WIX filter. I used to have a microgard, and it had WAY less filter element folds so it couldn't pass as much air as the WIX.

I think you should drive your car with the hole in the valve cover fixed as a hole in a valve cover could cause a vacuum leak through your PCV system.

Back to my issue - the shop threw on a new hub for me and was just about to wrap up with the valve cover gaskets, when they noticed a HOLE in the rear valve cover itself!!! They weren't sure how that would happen, but he thinks bad motor mounts might have allowed the bolt on the alternator to hit it somehow.


Thats ODD :confused:

Thats ODD :confused:


That's what I thought. Interestingly enough, they were the ones who replaced my alternator back in June. I really don't think that this shop is ever intentionally dishonest (I've been going there for ten years), but they do have their careless bouts every so often. The only real frustrating part is when I can't prove their fault in the matter - there's not much I can do...

I had my car in there not too long ago to get the tie-rod ends replaced. A week or two later I took my car to the tire shop for a free rotation. When I went to pick up my car I noticed one of the driver's-side front lugs was missing. I went back in and asked about it and they said it was like that when I brought in. He said that the stud was broken and someone had used a grinder to smooth the break and it only left like three threads for the lug to grab on to. I knew the lug was on it when I brought it in, but I couldn't prove that the stud wasn't broken. So either shop A broke it and didn't tell me or shop B lied - no way to prove it. Not a huge deal because it's just a wheel stud, but I get really fired up when I know someone is jerking me around, regardless of the cost.

This place causes me to question their quality of work about 15% of the time. I tried taking my car to another shop once and ended up royally regretting it.

I think you should drive your car with the hole in the valve cover fixed as a hole in a valve cover could cause a vacuum leak through your PCV system.

I thought about what you said and I'm tempted to because I really like to isolate the cause so I know exactly what's going on. I don't know if any of you have ever driven up Parley's Canyon here in Utah, but it's notorious for being a test of your engine's nerves due to it's steep consistent looooong incline. Going down the other side is the rotor warper. I've not once gone up that thing without seeing at least one car on the side of the road with a popped hood and smoke coming from the engine. Semi's have to almost literally crawl up that stretch of road and I always laugh when I see how much some people rap out their poor engines and try to fly up that thing. I had almost forgotten about this, but I took the Prix up there once (during the time that I was seeing these surging issues) and sure enough I saw the surging problem as I was driving. The weird thing was that when I got to the top and started to go down the other side, the torque converter would not disengage! If I touched the gas at all the RPM's shot sky high as if the car was literally in the air on a lift and I pressed the gas. It wasn't until my speed greatly decreased until I could actually use the gas pedal. This may or may not be related to my surging problem, I guess. The only time I ever saw anything like this happen was going up Parley's. I was thinking that after picking up the car I could take a buzz up that canyon and see how it does. If it acts up I could take the CAI out and try again. If it still acts up, I have more to look at for sure.

After all the repairs, the surging issue showed up again yesterday. I'll be putting the stock air box back in after I get a filter for it and will see if that solves it...

Good idea.

Update:

I've had the stock air box in for about a week now and last night it did the surging thing (very small) for the first time since making the intake switch. I know for sure, however, the issue has definitely improved because now I can't make it surge on demand like I used to. So I wonder if maybe this is normal if you hit just the right spot and having the CAI just made it more prevalent?
In any case, I do think putting the stock air box back on makes the engine seem much more responsive on the shifting which I never would have guessed to make that much of a difference. The other weird thing is that it almost seems like the throttle is a little more responsive too, which also surprised me.
At the end of the day, I think this corrected the problem enough where I'm no longer concerned about it. Thanks for all the help guys, and if anyone wants to add any last comments, feel free...

Update:

I've had the stock air box in for about a week now and last night it did the surging thing (very small) for the first time since making the intake switch. I know for sure, however, the issue has definitely improved because now I can't make it surge on demand like I used to. So I wonder if maybe this is normal if you hit just the right spot and having the CAI just made it more prevalent?
In any case, I do think putting the stock air box back on makes the engine seem much more responsive on the shifting which I never would have guessed to make that much of a difference. The other weird thing is that it almost seems like the throttle is a little more responsive too, which also surprised me.
At the end of the day, I think this corrected the problem enough where I'm no longer concerned about it. Thanks for all the help guys, and if anyone wants to add any last comments, feel free...

i would throw a shift kit in there...cant really hurt you to try. ZZP has them for $30 and that comes with the filter too.

Hmm. May give that a try after we move.

Now clean your MAF and unhook your battery for overnight.

When you hook it back up, it will have to re-learn all your driving habits and I have seen this sort of slight tcc gone after the unhooking the batt.

Alright, I'll give that a shot. Is there anything I need to know about disconnecting the MAF to clean it, or is it kinda plug(un-plug) 'n play? Any brand of MAF cleaner that is better than others, or is MAF cleaner, MAF cleaner?

Thanks!

Alright, I'll give that a shot. Is there anything I need to know about disconnecting the MAF to clean it, or is it kinda plug(un-plug) 'n play? Any brand of MAF cleaner that is better than others, or is MAF cleaner, MAF cleaner?

Thanks!

the sensor is pretty much unplug, remove and clean. in order to remove the MAF though...you will need a "secure" T-20 Torx bit. if you look at the bolts that hold the MAF in...there are little shafts in the middle of the bolt that the torx bit must fit over. as far as the cleaner...they sell actual MAF cleaner at the parts stores.

I cleaned off the MAF last night and found that it still did the surging thing afterward. While I had the sensor out, I took a peak at the throttle plate and it was really gummed up, so I'm going to tear that thing out and clean it really well. I doubt that would cause my problems, but it needs to be cleaned, regardless.

Has anyone ever used (I can't remember what they're called) one of those in-line oil catches that you place in the line that recycles the unburnt fumes back in the engine so you don't get the sludge on your throttle plate?

While I had the sensor out, I took a peak at the throttle plate and it was really gummed up, so I'm going to tear that thing out and clean it really well.

That is normal. The stuff you see is from the hot exhaust gases being recirculated back into the intake system. I clean mine out once a year. Make sure you use throttle body cleaner like STP brand and not the harsher carb cleaner so the throttle plate seals do not get damaged. An EGR block off plate helps but you will still get the carbon over a period of time.

Ok, thanks Bob. I was wondering. I cleaned the Jeep throttle not too long ago and I'm sure that was the first time it was ever done.
Bob, when you clean yours, to you take the throttle body all the way off? You have to get a new gasket if you do, right? What do you do with the throttle cables?

On my GTP the last time I did it I took the throttle body completely off and used a new gasket. Now before I sold my L67 Regal GS I left it on the car and used a rag and toothbrush because you can still get both sides of the butterfly plate if you take your time. Its up to you. I lube the cables with spray lithium grease.

Also, clean the IAC seat on the throttle body.

The car started doing the surging thing really bad over the weekend. I have no clue what is causing this...

Do you have a scanner or powertuner, or anything you can use to watch the data stream? I wonder if the cone filter oil gummed up your MAF.

The factory air box can flow about 800 cfm. In order for a 3800 to exceed 800 CFM, a non supercharged VIN-K would have to be turning about 8500-9000 rpm or a supercharged VIN-1 one would need to be running a ton of boost. So all the theoretical gains of a CAI are a moot point (other than in highly modded cars) seeing as how the stock air box can flow way more air than the engine can ingest, and a quailty paper filter can trap way more dirt than a reuseable gauze style. Most people that install a CAI just think they're going faster because the intake makes more noise (kinda like old school guys that flipped their air cleaner lids upside down so you could hear the engine roar as you stomped the gas pedal).

just wondering if you can give any further "proof" of this? im not doubting you, i would just LOVE to present this to a few other people but i need more then just "its what one guy on the internet said", which is all i can really find right now...

can you give a link or anything to back that up?

Do you have a scanner or powertuner, or anything you can use to watch the data stream? I wonder if the cone filter oil gummed up your MAF.


I got the MAF cleaner and cleaned the MAF off really well! The weird thing is that since then, it has been doing it worse! :frown: The other weird thing is that my gas mileage on my DIC has shot up as well! This one has me totally stumped.

Are you sure its not a seconday ignition misfire happening?

How could I be sure? What should I check?

I don't know for sure. I would watch the missfire counts for each cylinder as the surging is happening. But I'm sure thats hard without a scan tool.

I had the same problem with the engine surging only when I accelerated at highway speeds. I changed all the spark plugs and spark plugs wires and it has never run better. I would give it a try, but the difference in my situation is that I had the 5th cylinder misfire code coming up. Hope it can help!!!

Hmmm. I changed all the plugs not too long ago, but I haven't changed the wires since I bought the car back in '05. Might be worth a try...

What brand blugs did you use? I know for a while delco 41-101's had problems with cracked porcelin, sometimes causing a missfire.

Last November I was experiencing similar issues as you describe, the guys on here were very helpful, Some described it as Fishbite, Chuggle, Washboard, and TCC Lock, Started soon after a tranny fluid exchange @ about 103,000 mi, I usually play my music loud so I first felt it in my seat, kind of like a hiccup, then after a few times of feeling that I noticed my tach would jump a little 200-300 rpm's, mostly on the highway when going up a grade. Did the Air filter thing, MAF-check/cleaned, Plugs, Wires, Cleaned the electrical plug/contacts on everything related, seemed to get a little better with each attempt but came back noticeably soon after, No codes, No Nothing, So I dropped the pan, changed the filter, added +- 8 qts of DEXVI and a bottle of Lube Guard Red and the issue was gone and has not come back since, it has been 10 months and 24,000 mi. Not sure if the issue I had is related to yours, but if you've done all the other things you said and have not replaced the tranny filter? I would definitely recommend that you do.

Good Luck...

Tim,

I put in Autolite platinums last year I believe it was.


DC1263,

Thanks for your input. It so happens that I had a tranny fluid and filter changed (no flush) about 9K miles ago.


I got to thinking about the plugs and wires. If those were the cause of my issues, wouldn’t I notice those problems regardless of the speed/engine load? I don’t understand how something like that would only be manifest going 55-70 MPH and no other time?

I was stewing about this some more and remember a few years ago when I was telling a friend about this issue (then thinking it was my custom CAI being too restrictive). He suggested that I put some Lucas stop-slip additive in with the tranny fluid. As I recall, it didn’t solve my problem, but did help enough to the point to where I was able to ignore the occasional RPM hiccup on the freeway. Then I noticed that when I got the next tranny service done, the issue seemed to resurface. After cleaning the MAF the other week, the issue is worse than it’s ever been. I wonder if I should get that lucas stuff again and see what happens….

Ac Delco Spark Plugs 41-101 and Ac Delco Wires

Tim,[FONT=Arial]I got to thinking about the plugs and wires. If those were the cause of my issues, wouldn’t I notice those problems regardless of the speed/engine load? I don’t understand how something like that would only be manifest going 55-70 MPH and no other time?

Simply put, the combustion chamber pressures are the highest when the trans goes into overdrive lockup. This makes it harder for the spark to jump the gap across the spark plug. Often times it doesn't, and archs right through the spark plug boot or tracks down the boot along the spark plug porcelin (carbon tracking). This happened to my G/F's 02 SE. A new set of Plugs and wires solved her issue.

I forget now, are the wires still the stockers?

I forget now, are the wires still the stockers?

It's likely. The car has 130K miles on it and when I bought it, it had 68K I think. I haven't changed them since I've owned the car.