Ecotec 2.2 in a LT Balt automatic Coupe, been fighting misfire and stalling issues since freaking NOVEMBER.

What I've done:

Started stalling on me in Nov. Hubby thought fuel filter, so we had that changed at the local mechanic (not MY wrench, but a guy my hubby knows pretty well). (Right around 63xxx miles.)

Kept stalling, threw a couple codes that suggested throttle body codes (can't remember exact ones). Cleaned throttle body and reset codes. Threw them again, so eventually replaced throttle body (brand new GM part) in Jan.

Kept stalling with no codes. Finally some popped up in Feb, misfire on 1 & 3. Hubby changed plugs with Autolite platinums, even though the orig. Delcos didn't look bad at ALL. 64xxx miles.

Still stalled, no codes, and hubby cleaned MAF sensor. She finally threw misfire on 1 & 3 codes again. My wrench changed coil pack (again, new GM). (March)

Threw codes again for 1 and 3. Replaced all 4 fuel injectors (you guessed it, new GM). (April)

Started throwing the random misfire code in late May. My wrench hooked it up to his one computer and saw that she's now misfiring on all 4 cylinders. 2 and 4 had a slight miss on them all through this whole ordeal, but it was never enough that my wrench was worried about. Rechanged the plugs, this time with Delcos. Ran like a CHAMP for about a wk and a half, then started misfiring again. Threw the P0300 code again last week.



Has anyone on here actually been able to SOLVE their misfiring issues in ways other than I've mentioned above?? I've seen talk on the ecotec forum about the ICM being the issue, I've also seen talk of it being the engine computer. I've been lucky enough to not to have had to throw TOO much money into all of this (less than $700, and that includes my 4 new tires), but it's getting to the point where this thing is just nickel and diming me like crazy.

For some strange reason, I really do LOVE this car, and am totally hell-bent on getting her fixed and running like the champ that I know is down in there somewhere. She did for a while, and I know it's THERE, I just haven't figured out how to KEEP her there. She's a great car, and once I can get this taken care of, I know she's only about halfway through her life, at least mileage wise. (She's at 65600 some now.) Thanks!!!

 

Forgot to add that the alternator was changed (new GM) back in Jan. It wasn't changed as a result of the misfiring/stalling, but due to an accident I was in where the old one got pretty tore up. (Not sure if this is relevant, but wanted it in here if it is.)

 

Check your coils. You should be able to replace all 4 for around 100 bucks or so, and I know they have solved misfiring issues on a couple other cars.

Edit: Nevermind, I see you tackled that already. Damn.

Maybe bad ECU or even the timing is somehow off? If the timing tensioner is bad I believe it's possible for the chain to jump a few links.

 

I think a member on here named Rukke or something like that ,had issues similar and it was deposits in the fuel rail.(this would cause fuel starvation to the injectors and cause misfires)
Its something you havent tried.
Another thing is the cam sensor or crank sensor being bad causing the stalling issues,the timing for the
Engine spark being taken from these but Im not 100%.

 

A friend of mine had a real bad fuel rail issue on a 05 SS/SC . It was misfiring and cutting out bad over 4500 rpm so we pulled the rail to look at the injector's and found there was crap everywhere .... in the rail.....in the injector's and even in the fuel line. He had just had the fuel filter replaced but this stuff was in the system somewhere past the filter cause there is no way this stuff could have got past the filter without plugging it .

Here's about 1/4 of the stuff that came out ..... when we flushed the fuel line I caught it in a can and this is what was in it......