intermittent miss, no SES, no codes. [Archive] - GrandAmGT.com Forum

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nomojo
03-17-2004, 11:07 PM
Hi guys

Looking for any input you guru's might have. Maybe someone knows of a bulletin or something that can help me? I apologize for the long windedness of this..

I used to have a '99 grand am SE and I absolutely loved it, so when it was time to get a new car, I decided to go with the '03 GT.

Since I've got the car, its had a horribly annoying misfire problem.

Here are the wierd details / history / life story:

Since i got the car new, when i would drive 100km/h (about 60mph) steady, approx 1900 RPM, the car would surge intermittently. It was really only noticable at this speed. It would feel somewhat analogous to the 'tug' feeling of a lure when a fish is biting. No SES light (ever) has come on.

I took it into the dealership, and there were no codes. They test drove it, said they couldnt find anything wrong with it.

More time passed, and the problem didn't go away. I took it back. I left my car with the dealership for a week so they could screw around with it and drive it. On the last day, they got it to act up exactly as i stated, and they had the Tech2 scanner attached.
From what I understand, CYL2 was misfiring like crazy. They swapped plug 1 with plug 2 and re-drove, but it still did it. Apparently there was a TAC from GM describing this, and the solution was to clean the head of the engine with cleens which removes carbon deposits (I found this quite odd considering the car had < 1500 kms on it). They did this, re-test drove it the next day, and indicated that this fixed it.

Unfortunately, i was out of the city when they fixed it, and the car sat about a month.

The problem was better when i next drove it. The harsh miss was gone, but it still acts up (really odd feeling, kinda like stuttering. It doesnt feel like rotors, brakes, or a busted tire in any way to me). Again, not as harsh as it was before.

Apparently the dealer did the drop test on the injectors, etc, but nothing showed up. Ive had the car in a number of times since, but they can't find anything wrong, and because the beloved on board computer says everythings fine, it must be so, right? (heh). I went out one more time with the tech while I drove it and it missed when I was passed somebody (miss on cyls 1 thru 4, cyl 2 missed the most # of times). They analyzed at the data on the tech2 and said they couldnt find anything that would cause it, and stated that 'its normal under some circumstances for this engine to miss'. I'm quite satisfied with the competence of the dealership I'm going to: everything they've ever done to my 99 was done right the first time, unlike every other dealer ive ever had to deal with; and they're always really fair, so I'm kinda stuck on this one. (plus, they're getting sick of seeing me in there complaining about the same thing all the time).

I'd love (not) to believe that this 'miss' is normal, but like I said I had the 3400V6 in my '99 SE and it DID NOT DO THIS. Maybe its something different, but under the hood, it looks basically like the 99 SE V6 to me. Tires are different, yes, gear ratio is different, yes, but tranny & engine are the same, so theres gotta be something..

Any ideas? I don't really want to complain to Pontiac because I like the *look* of the car, and really, who enjoys dealing with them? but its performance is really turning me off. Mayhaps GM is a stay-away-from in the future? I've had a number of other problems with the car (wind noise from rear, adjust rear seal, driver side power window assy broke in first 3 months, etc) since I bought it which really leads me to believe the quality control is really poor with GM.. Who knows.

I'm thinking of changing the wires to MSD's, even though they tested the ones that are on it now (factory) and said they tested OK. They've also since replaced all of the spark plugs. I'm going to switch to NGK IX's (ive got them, but havent installed them yet). I doubt this will fix it but im grasping at straws.

If anyone has any ideas, please let me hear them

Thanks!!

nomojo
03-17-2004, 11:16 PM
Oh, probably unrelated but just in case.

There is an intermittent bad idle with the car as well, and I dont know whether they changed something or not, but my headlights dim whenever anything that requires power comes on (headlights & int. lights dim for a second and the brighten back up when brakes applied, etc). I checked, and I had them check, the connections to the battery & at the fuse box, and they said everything was fine. Maybe the power thing is a change to the design of something in the 03.. maybe GM saved another 2 cents per car by removing some part somewhere ;) When the idle is rough, the lights dim according to the idle speed.

Again, don't know if this information helps a diagnosis or is completely unrelated, but thought I'd mention it.

Thanks again for reading and hopefully someone out there has an idea!

cheers.

Dr_Kyle
03-18-2004, 12:07 AM
I'm stumped..

If the injectors, wires, and plugs are okay.. maybe it's the coil packs? The only other thing I could think of would be the TPS, but I doubt that's the problem.

illsmokeyou
03-18-2004, 01:36 AM
I also thought the coils, possibly bad IAT?? but then again, the car has so few miles as you stated

DO NOT modify any ingition (spark) wires to anything aftermarket until the problem gets solved. GM will thank you for swapping ignition wires for aftermarket MSD's and "claim" you are now at fault

I dont know what your lemon laws are up there, but pretty much in the US, the manufacturer has 3 attempts to correct the problem, and if they cannot do so, or your car is in the shop for at least 30 days out of a year, they are obligated by lemon law to put you in a brand new '04.

Keep taking it back and demanding that the problem has not been fixed, since they already acknowledged the origional problem, all you have to tell them is your still having the same symptoms.

Bottom line is that you paid $$$$ for a brand new vehicle, and you should expect nothing less

swordfencer
03-18-2004, 08:44 AM
Hmm, maybe check the alternator and see if it is dying? That is the only other thing I can think of. But yea, I am also betting it could be the coilpacks. They can go out after only 1500 miles or so. VW was famous for their coilpacks dying out around 1000miles or so. Could also be a fuel pump or injector maybe too.

nomojo
03-18-2004, 06:05 PM
Thanks for all the input so far guys.. I really appreciate it.

I was thinking it might be something snakey in the fuel tank or filter or something, maybe someone sabotaged it when it was on the line at GM (mayhaps a disgrunteled worker? who knows).

I would tend to agree that it might be one of the coil packs; i was also thinking it might be a flakey wire.. but what I dont understand is why the on board diagnostics arent recording this or acknowledging a problem: the computer knows about it (it says theres a miss on the tech2 while its being driven)... Can you have a bad coil pack / wire without SES/ stored codes?

As far as the replacing the wires/plugs, I agree; im hesitant to change anything cuz I dont want GM to try to blame me; that said, I do have a great deal of logged 'pre-messing-around-with-the-car' service reports. Maybe i'll just do the plugs alone and leave the wires?

The other thing that I'm up against is that theres only the one tech at the dealership that has ever felt it do it. Its so incredibly finnicky: you have to be driving it just right, and its just so intermittent. It seems like when I drive, it does it. When the guy who can fix it drives, it doesnt. Ain't that always the way. I started to think I was going insane until I talked to the tech who drove it. Fortunately, he said 'Oh i know it does it, i felt it do it before, and i just felt it do it now. Its quite sharp.'.

I think the dealerships hesitant to randomly replace parts with no basis or evidence that they're broke, for GM may not reimburse them if they start sending good parts back. Maybe I will have to get Pontiac involved in this afterall. What a PITA.

Thanks again guys, and if anyone else has any ideas feel free to post 'em.

cheers

illsmokeyou
03-18-2004, 08:24 PM
NOPE>>>> DO NOT replace the plugs either....keep the factory delco's in

back in summer of last year when I had rapid misfires around 1800 rpm, in any gear....... I made the mistaken of noting to them that I had changed out the factory delco's for Bosch, after they questioned me about my taylor wires. And of course, they denied to look at my car under warranty because I had changed the factory delcos out....... if your gonna change them out because theyre faulty....... guess WHAT???.... theyre covered under warranty anyhow, so youd be wasting $20 on new plugs. Long story short, I threw on the factory wires and delco's back in and to no suprise still had the misfires..... but the problem was found

If GM has a reason to get out of it, THEY WILL, dont give them that opportunity!!!!!!!!!

illsmokeyou
03-18-2004, 08:27 PM
BTW.... have you messed with the crankshaft pulley or sensor???

this is beggining to sound in that relation

nomojo
03-19-2004, 08:02 AM
Originally posted by illsmokeyou
BTW.... have you messed with the crankshaft pulley or sensor???

this is beggining to sound in that relation

hey

thanks for the advice

nope, i havent messed with anything yet :) most i've done was change out the stock air filter for a K&N drop in.

looking through the service manual, the crankshaft position sensor could be it too, but again, with no codes/ses light?

I dont know how I'm gonna be able to go in there and ask them to start arbitrarily replacing parts.

stupid car :)

nomojo
03-19-2004, 08:05 AM
Originally posted by illsmokeyou
NOPE>>>> DO NOT replace the plugs either....keep the factory delco's in

back in summer of last year when I had rapid misfires around 1800 rpm, in any gear....... I made the mistaken of noting to them that I had changed out the factory delco's for Bosch, after they questioned me about my taylor wires. And of course, they denied to look at my car under warranty because I had changed the factory delcos out....... if your gonna change them out because theyre faulty....... guess WHAT???.... theyre covered under warranty anyhow, so youd be wasting $20 on new plugs. Long story short, I threw on the factory wires and delco's back in and to no suprise still had the misfires..... but the problem was found

If GM has a reason to get out of it, THEY WILL, dont give them that opportunity!!!!!!!!!

... hey, rapid misfire at 1800RPM? did it set a code or engine light? That 1800 is the magic mark where im having my problems. Related?? What was your fix?

mfuller
03-19-2004, 08:38 AM
Originally posted by nomojo
hey

thanks for the advice

nope, i havent messed with anything yet :) most i've done was change out the stock air filter for a K&N drop in.



Put the stock paper filter back in, and check the MAF. There have been reports on GM trucks that aftermarket oiled filters (like K&N) can mess up the MAF sensor.....although it usually only happens if the filter has ben over-oiled. Just a thought.

brdrxtreme
03-19-2004, 09:06 AM
i have a 2004 se 3400 v-6, i have that same annoying ass miss... dealership also said it ,ay be "normal" for my engine to do that. it does at 60 mph and up after a good steady drive. also has a definent shutter at idle speeds but i work so much i cant keep goin to the dealership. lemme what the outcome is when u figure it out!!

nomojo
03-19-2004, 10:58 AM
Originally posted by brdrxtreme
i have a 2004 se 3400 v-6, i have that same annoying ass miss... dealership also said it ,ay be "normal" for my engine to do that. it does at 60 mph and up after a good steady drive. also has a definent shutter at idle speeds but i work so much i cant keep goin to the dealership. lemme what the outcome is when u figure it out!!

Hmm. I wonder if they busted something with the small "revisions" they made to the tranny and engine starting in '03. g'dit, if it aint broke dont fix it! :)

By the sounds of it there are others out there, so if you have this problem drop a note or something. Problem is your average driver may not notice the problem. AAA! frustrating.

nomojo
03-19-2004, 11:00 AM
Originally posted by mfuller
Put the stock paper filter back in, and check the MAF. There have been reports on GM trucks that aftermarket oiled filters (like K&N) can mess up the MAF sensor.....although it usually only happens if the filter has ben over-oiled. Just a thought.

Hmm. I will definately try that. I probably overoiled my filter. Wouldnt that be awesome if that fixed it...

I myself dont have a tech2 or any other sort of scanner... so when you say "check the maf", other than eyeing it and making sure the connection to it is good, is there anything else i can do?

thanks again

iceman
03-19-2004, 11:30 AM
I had similar problems and it was clogged injector, no codes or anything.. I know some other people have stated this, sorry if it doesn't apply to you.

illsmokeyou
03-19-2004, 03:51 PM
Originally posted by nomojo
... hey, rapid misfire at 1800RPM? did it set a code or engine light? That 1800 is the magic mark where im having my problems. Related?? What was your fix?

that was my crankshaft sensor that was bad, and was not reading the reluctance ring in the crankshaft pulley..... and it did not set NO code.... ultimately, it got replaced under warranty

like iceman said, there is a TSB for clogged injectors also ;)

nomojo
03-20-2004, 12:27 AM
Originally posted by illsmokeyou
that was my crankshaft sensor that was bad, and was not reading the reluctance ring in the crankshaft pulley..... and it did not set NO code.... ultimately, it got replaced under warranty

like iceman said, there is a TSB for clogged injectors also ;)

hmm. as far as injectors, shouldnt be those, they cleaned them and ran a drop test on them.

how did they diagnose the CKP sensor? Better yet, to avoid having to deal with .. well. dealerships, is there a way i can test it easily? is it something they would notice on the Tech2 scanner or not so much?

im gonna swap out my air filter like a few msgs ago suggested and see what that does, too.

Thanks guys for all the input & help

cheers.

illsmokeyou
03-20-2004, 01:37 AM
Originally posted by nomojo
hmm. as far as injectors, shouldnt be those, they cleaned them and ran a drop test on them.

how did they diagnose the CKP sensor? Better yet, to avoid having to deal with .. well. dealerships, is there a way i can test it easily? is it something they would notice on the Tech2 scanner or not so much?

im gonna swap out my air filter like a few msgs ago suggested and see what that does, too.

Thanks guys for all the input & help

cheers.

youd hav eto do a search, but you would need to tap some wires at the PCM and check the voltage signal thats incoming

nomojo
04-08-2004, 09:48 PM
Hmm, heres an update.

Putting 91 octane in the car really seems to help it out. It still does its little hiccup thing, but no where near as much. I also changed the air filter back to stock, it wasn't overoiled afterall, and it seems to not have made any difference. (d'oh!) If anyone has any ideas why the higher octane would perform better for a car thats supposed to take 87 (and the PCM AFAIK is calibrated to 87), feel free to raise your voice :)

As a possibly completely unrelated side note, I've noticed that I don't seem to have terrible piston slap in my '03 like I had in my '99.. maybe cuz things are new they're tighter?? Its still very very slightly audible but on my '99 you could hear it over an orchestra (...).. Maybe the extra 'tightness' is causing things to stick and causing misses? who knows.

Anyways, if anyone ever find out about a TAC or service bulletin or anything for this let me know.

Blight
11-29-2004, 03:20 PM
Mine did the exact same thing. Maybe youll never see this its so old lol, but i finally had a code thrown for a split second i saw SES come up and it said bad crankshaft sensor.

nomojo
12-11-2004, 09:46 AM
Hrmm. Thanks for the post, Blight. Still no codes, but it seems to have tamed down a bit with some engine wear. I'll keep you guys posted if I ever end up throwing an SES