Engine mis-fires, hesitation from start, and poor fuel milage (hate to add another..)

All:

Hi I'm new here, and have been reading along many other threads regarding my same symptoms, but thought I'd throw my issues in the ring anyhow.

We just recently (fall) traded up our '98 Grand Prix for an '04 GrandAM GT 6 cyl, love the car, but.....

Since the late fall we began noticing a small lurch or 'miss' under slight load (up a small grade say or pulling away from a stop position), or just on flat surfaces at reduced RPM (due to overdrive gear etc....). The latter could be say 70KM/hr (maybe 1200-1400 RPM) or 95 - 100 KM/hr at 1800/1900 RPM. Not all the time, and naturally not repeatable when you are having someone look at it!! We've had it to the dealer countless times for this issue (10 - 12?)... a couple times they had indicated they had it working so poorly that they could hear the resulting problem in the exhaust. However, most times (the other 8 to 10 times) they simply returned the vehicle saying they couldn't duplicate the issue (and usually on the way home it would then do it for us again, very frustrating). Also of note the fuel mileage has bottomed out... we are lucky to get 350km (400 if VERY lucky) per 45 to 50L tank. This works out in imperial MPG to be about 20 to 25MPG (our GPrix for reference generally got 30MPG; 25 in winter/town and was bigger engine). The common things seem to be +/- 1500 RPM, outside temperature say from 0 C to +/- 5 C, and dampness/wet seems to be help the problem surface

There have been no codes tripped recently (the SES light was at one point before X-mas). The dealer provided us with a portable diag recorder, which we collected data when we felt the vehicle doing it's thing. No real codes, but they did pick up Torque Converter issues I guess... they replaced some sort of pressure solenoid, but that did not correct the issue. They did change the plugs, air filter (45000km, now about 51000) and indicated there was lots of spark etc. even though the plugs I guess were a bit fouled before changing (I suggested plug wires).

Long story short, they basically have exhausted their time to look into this for us unless it trips codes or becomes much worse. However, we are still feeling the problem, so there is still an issue. Also, during the real cold snap this winter (say -15c to -20c) I thought I could hear a small 'backfire' noise upon initial ignition from the tail pipes. This only seemed to happen in the extreme cold.

I have since had an independent mechanic look at it with his tester and knowledge as I really want this addressed. He used the tried-and-true method of checking plug wires and noted that in complete dark after moistened, he noted definite arching of fire from at least one wire, possibly two. Also, his tester didn’t generate any definite codes, but there were faults (misfires) reported on Cyl's 1 and 4 I believe he said.

He changed the plug wires for us, and after a week or so of driving and some damp weather has come back, the problem still persists.... ARG. Naturally the plug wires shouldn't have been arching, but that evidently wasn't the full solution as yet.

Where to go next? Coil? Fuel System? I think I read on here that the lay out of the Cyl-to-Coil indicated Cyl 1 and 4 went to one of the coils.

Also of note: the car is equipped with an after market remote start as well (I've seen this referenced here as well).

Any tips, sorry for the LENGTH!

... can extended periods of bad plugwires etc. damage a coil?

[drumking1721]

Idk about the coil so much....plugwires wont give the proper spark to the plug and may not fire right and all that good stuff

Originally Posted by drumking1721

Idk about the coil so much....plugwires wont give the proper spark to the plug and may not fire right and all that good stuff

.. So maybe a bad set of after market plugwires? If there was to be such a set, I'm sure I'd get them :-(

Thanks for the message,
Chris

[gectek]

i would def look at the ignition control module and the coils and get a good set of wire looms to isolate the plug wires.

Originally Posted by gectek

i would def look at the ignition control module and the coils and get a good set of wire looms to isolate the plug wires.

Great, thanks for the message! Ignition control module which is under the coils good thought... while on the topic of 'ignition'... another symptom besides what I mention of the slight bogging out as you leave a stopped position, when you first start the vehicle, the engine surges a bit as it starts (somewhat normal), but then almost dies out before 'catching' and coming back to idle (doubtful this is normal). And, to top it off, it really doesn't appear to be idling high enough once it does stabilize itself. Also, things such as lights and defroster/blower fan are VERY dependent on this action... blower fan will blow stronger when accelerated, lights sorta dim out a bit as it's idling type thing... not bad, but more than I've witnessed in other vehicles. This, and of course the continued occasional herky-jerky feel when (what appears to be the mis-fire) traveling at 60 to 70 KM/hr (35-40 mph?).

For reference, when I start my Pursuit (G5), there is none of this engine rev, bog out, then back to idle... it snaps on, and goes to steady idle as it should. Granted, entirely different engine and 4 cyl etc etc, but still.

I beginning to doubt this is going to be found until either something breaks bad and/or the problem worsens and starts tripping codes.

Crank sensor??

[drumking1721]

Sounds like the ignition

[gectek]

werd...also look at fuel filter and maybe some good GM injector cleaner and do a top engine clean as well...should be a how to on the top engine clean thing. if u do look at coils and maybe find a bad one, i would go and replace the ICM as well and all the coils just to be safe and the MSD coils are actually cheaper than the others and are higher output. also make sure to use dielectric grease for all connections, both on the icm, plug wires, and the primary post that plugs in the bottom of the coil

Originally Posted by gectek

werd...also look at fuel filter and maybe some good GM injector cleaner and do a top engine clean as well...should be a how to on the top engine clean thing. if u do look at coils and maybe find a bad one, i would go and replace the ICM as well and all the coils just to be safe and the MSD coils are actually cheaper than the others and are higher output. also make sure to use dielectric grease for all connections, both on the icm, plug wires, and the primary post that plugs in the bottom of the coil

Thanks for all this useful advice! Very much appreciated. I do see there are few spots mentioned in Canada for MSD ignition supplies...

I have purchased GM Inj Cleaner, but haven't used it yet (been using the over the counter stuff a few times... every couple of tanks since Jan I guess once the dealer help started to go away...). At about 3 to 4 x the cost, I was waiting to see if the problems(s) could be better isolated before using it. I think I will end up using it anyhow at some point, but wanted to give the current guy some time to look into the problems with his scan tools etc. before adding anything more to the mix.

Another strange or odd question: would there be anything that anyone could think of that would actually be damaging the plug wires (overload, break them down, whatever...)? The reason I say this, when the new plug wires were put on, there was a few days that the car actually seemed to work ok (in fact I thought it may have even been fixed!), about 1 week later, we are back to the same issues. Just a thought (besides the wires themselves being bad from the beginning I mean), they were NAPA bought wires. The startup seemed better, the leaving from a stop seemed more responsive, idling seemed improved etc. , then now back to the same issues...

Can the wires be damaged by some underlying issue that we haven't isolated yet (in case we were to try another set ;-))?

Thanks

Update: It appears after the guy has relooked at it, the replaced plug wires were arching more than the original ones replaced.... =8-o (DOH!) so we are deploying yet another set (what are the odds???). If these don't work for whatever reason, (unless something is blowing them out which I can't imagine what given the Voltage they should be normally capable of handling) I will have to explore and seek out a higher grade performance style brand if i can find some locally....

I will update on how this unfolds... :-)

Well, a quick update. Plug wires were replaced again, coils were taken out, inspected/cleaned etc., plugs looked ok (a bit carboned maybe, but equally so)... the results are that the car is still acting up. Going to revisit the dealer again now that a few things have been tried on the side.

Leaning toward Ignition Control Module, Crank Senor, or Primary Computer (PCM?). It was spitting and sputtering quite bad at around 90km/hr for an extended highway drive a couple days ago when I had it out... hoping I can duplicate this when the dealer has a look again, though it does seem to go in cycles (or resets? hence the computer theory). Also, wife indicated that she was waiting at lights to pull across traffic to make turn... when she got her chance, the vehicle bogged and sputtered so bad she wasn't sure it was going to make the turn. Still has a problem by times pulling away from a stop position. However, today she indicated it only made that miss sensation maybe a time or two during her trip to work... getting VERY frustrated.

I can't imagine we got *2* bad sets of plug wires. I had a look after dark and there was no glowing or arching that I noticed on this set.

... anyhow... as they say, on it goes.

[XtremeGaGt00]

i coulda sworn i had this problem before...and i THINK they replaced my MAP sensor...fixed the problem...dont take me up on that offer tho seriously...im not exactley forsure

[NorKoastal]

Clean /Replace your MAF sensor..

This might be dirty and throwing off your RPM's and causing delayed throttle response... My Maf was routed through a ICCU unit and it did the same thing your talking about (cycling RPM's and delayed throttle response) when a wire slipped out of the connection pot.. After that I would Seafoam through the PCV tube, throw some in the oil and gas and test her out... Change the oil about a week after the sea foam was placed in the oil..

Good Luck..

Ok, great, thanks for the new comments. Been doing some reading here and other places about MAS and it's related symptoms. Like 101-parts (:-)) that could be bad when you are experiencing this type of stuff, it certainly sounds like it could be it. It's just too bad it's not tripping any codes (that I'm aware of, no scan tool) or triggering SES lights etc.

The only time we had the SES light was when we had into shop one time for this same problem, but of all ironies and timing, the bearing assembly was replaced as well due to the ABS light etc. being on as well. When they reset the codes, naturally both sets of lights went off. Haven't seen the SES light since and they indicated it likely came on due to the other fault due to the ABS sensor/bearing issue (??!).

.... and, because it's and my car, with the luck I seem to be having, we are just over 50,000km, both bearings have been reportedly replaced between 40 and 45,000 km, there now is a new "swishing" (kinda' like rusty metal on rusty metal sound) sound coming from the front end again in rhythm with the speed of the wheel turning speed. Thought is may be brake/caliper holding on a bit or rotor issue, but had them taken off and checked and they appeared fine. The sounds appears to be closer to the RF/passenger side, but I'm not 100% convinced it's not a bit more toward the center of the vehicle now. Anyhow, something else for them to look at. It does seem to get a bit more noticeable under steering, and you can really only hear it at extreme slow speed (parking lots etc)... once at speed it either is a constant steady sound, or whatever, but it can't be distinguished... In some strange way, this couldn't be a worsening symptom of the poor engine performance could it (some component rotating and failing...)???

Geez... one problem at a time please :-(

[NorKoastal]

Originally Posted by cgouch2

Ok, great, thanks for the new comments. Been doing some reading here and other places about MAS and it's related symptoms. Like 101-parts (:-)) that could be bad when you are experiencing this type of stuff, it certainly sounds like it could be it. It's just too bad it's not tripping any codes (that I'm aware of, no scan tool) or triggering SES lights etc.

The only time we had the SES light was when we had into shop one time for this same problem, but of all ironies and timing, the bearing assembly was replaced as well due to the ABS light etc. being on as well. When they reset the codes, naturally both sets of lights went off. Haven't seen the SES light since and they indicated it likely came on due to the other fault due to the ABS sensor/bearing issue (??!).

.... and, because it's and my car, with the luck I seem to be having, we are just over 50,000km, both bearings have been reportedly replaced between 40 and 45,000 km, there now is a new "swishing" (kinda' like rusty metal on rusty metal sound) sound coming from the front end again in rhythm with the speed of the wheel turning speed. Thought is may be brake/caliper holding on a bit or rotor issue, but had them taken off and checked and they appeared fine. The sounds appears to be closer to the RF/passenger side, but I'm not 100% convinced it's not a bit more toward the center of the vehicle now. Anyhow, something else for them to look at. It does seem to get a bit more noticeable under steering, and you can really only hear it at extreme slow speed (parking lots etc)... once at speed it either is a constant steady sound, or whatever, but it can't be distinguished... In some strange way, this couldn't be a worsening symptom of the poor engine performance could it (some component rotating and failing...)???

Geez... one problem at a time please :-(

One thing that might be a culprit is a rubbind shied behind the front rotor.. Double check that the metal plate isn't scraping the inside of the rotor...

I would get the Air sensor area of the engine bay checked out.. Your air fuel mixture might be all goofed up if these sensors are dirty and throwing false reads.. Let us know how things go..

[justinw]

I have the same problems as above on a 99' Alero. (fluctuating tach when started, hesitation on acceleration). New plugs and wires seemed to help somewhat, but only somewhat.

[justinw]

This GM bulletin might apply (99-06-04-050). Not sure. GM techs?

The hesitation stumble is really bad at times.

[gectek]

there are like 4 or 5 bulletins that may apply, most of them have to do with contamination of the MAF due to over oiling the filter, or a few other things. only way to know for sure is to take it to the dealer or try the testing and fixes yourself

Sorry for being a bit stupid here, but 'over oiling the filter'.... this would be the Air Filter? I've had air filters changed on previous vehicles, and maybe I wasn't paying strict enough attention or doing it right, but I don't recall having one oiled before being installed... I could have sworn it was just a matter of going to parts store, buying the filter, opening the compartment and deploying the new one in place of the old...

Where does the 'over oiling' occur?

Man, I'm hoping it's something relatively simple like a grimed up MAF sensor... and not like bad compression in the motor or something.... =8-o Though I think my symptoms would be a lot worse... also plugs look ok and equal (though the gaps may be more than 0.060, but they were dealer replaced, so they should be correct).

I did forget to mention, the very first time the vehicle was in for this issue back in November I believe, the very first thing they did was change out the Air Filter, and they indicated to my wife that it was "chock block full" (this was a new to us car, and it was at about 44,000km at that time, we'd had it less than a month then). If the filter was that polluted, it's conceivable I suppose that contaminants have messed up the sensor behind it as a result??


As ALWAYS, I REALLY really appreciate the feedback, suggestions and responses from all of you.

PS: any info on the bullitens mentioned or the general info contained in them would be nice to read regarding this if someone has them....

... had our oil changed today, and that appeared normal and fine, so more (good) information... I have been keeping an eye on the oil and coolant anyhow, but it was good to hear when it all came out during the change it still looked fine.