My bet is on bad coil since a few have died. But'* it is one or the other. Coil or plug. We dont have the wires to worry about.

i know it would make it gutless for sure but would a bad coil/plug make that difference in the exhaust tone?

EDIT: congrats on passing the 15000 posts! you need a GMFWhore Badge

Yes a misfire is for sure going to change the exhaust, AND it'* throwing a fault code. You can't argue with that. Either the plug or the coil is bad and that compounds the problem. Because of other sensors like 02 are trying to compensate other things. So not only are you running on 7 cylinders, it causes an imbalance and it affects the other in that the O2 and other sensors try to compensate the richness they detect and can't correct.

Didn't even see the 15,000 coming up LOL Thanks. Wish it was all postwhoring. Adminning is a far greater task that I thought coming in. But worth it to get this place where it is, and away from what it was.

Drive for a while and hope you get a code telling you which cylinder. Otherwise it'* pull all the spark plugs. You will know when you get to the bad one.

I wouldn't drive it anywhere but to the Dealer. You have right/left manifold sensors and upstream and downstream cat sensors. Why risk fouling them with raw gas. Or cause a backfire in an all aluminum engine with nylon intakes/valve covers and gear driven cams. Especially being the car is under Warranty. Their equipment can tell which plug or coil isn't firing. That warranty is worth a minimum of 10K for a crate engine and installation, and has enough fine print clauses to take it away from you without playing around.

Thanks guys
No GM wouldn't even know I scanned it
She'* going in tomorrow, and they can deal with the misfiring and all that crap, I'm just curious that'* all
Warranty good for another year, might as well take advantage of it ahahaha

If it'* still under warrinty, then ya, have them do it. I thought you wre out of warrinty. So my bad, let the dealership do what you paid for.

yea i will
there are few other issues with it too
its leaking oil, the HUD switch half of it doesnt light up, SES is on because of the vaccum pump, and some other stuff here and there

so i just called GM right now, they just took my car in half hour ago, i dropped it off at 730 AM.

There are no major updates yet, service advisor said the only thing done so far was they reflashed my PCM for some reason, he still doesnt know why, and i have some problem in cylinder #2.

not much info at the moment but he will update me soon

Good news:
HUD switch is to be repalced under warranty, to be ordered and it'll come in in about... ugh one day..
Car stalling/weird noise is coming from a bad coil on cylinder #2, to be covered by warranty. Ordered and to be in tomorrow.
PCM was reflashed because the Secondary Air Injection was fine, but the PCM was showing its not, so they reflashed it and it fixed the problem.. for some reason i didnt buy that one.

Bad news:
My oil cooler lines are leaking VERY bad, and they are NOT covered under warranty. parts and labour is going to set me back somewhere around $1300.00. and not to forget my $200.00 deductable. so thats $1500.
insurance news about the bumper is so and so, shes gonna let me know after i file up a police report., if they dont cover it thats another $2000.00 for a new bumper.
FML!