i have a 2008 ss turbo. the past few months i"ve been getting random missfire codes in all 4 cylinders. usually just cleared codes and go about my day. i had factory ac delco plugs gaped to .36. today i swapped the plugs i used NGK iridium same gap. engine ran great for about 8 hours no issues. but it started missing hardcore under acceleration. car sounds like a WRX going down the road. i checked codes and it said random missfire all 4 cylinders total of 7 codes. ive been reading the fourms but only thing ive come up is maybe my injectors...but id think id get injector codes and id say a coil but id think it would be on just one cylinder not all 4. if anyone has had this issue or know what it could be please help im at a loss of what could be wrong.
here is a list of my mods if it helps.
catless downpipe
upper and lower hahn pipes
hahn cold air
hahn intercooler
GM stage one tune
forge sert valve
thanks

 

Um the subi sound is bad, I don't remember what it is though. Search subi sound on cobalt ss. And plugs should be gapped to .32

 

Subi sound is usually either a faulty coil or broken rocker or similar in the valve train.

But being all four makes me think severely gunned valves. How many miles on the car?

 

Pull your valve cover, check your valve train.

If all looks well, pull your injectors and go from there.

 

Car has 86k. And ill defiantly will be looking at those things. What exactly should I look for with injectors? Top end ill know what to look for but not sure how you can tell if injector is bad? And has anyone used the opel injector set from zzp before kf so is it worth the $350 for all 4.

 

The opel injectors are definitely worth it if you're turbo swapped ect. You're basically checking the seals on the injectors. I think there's a thread somewhere describing the subaru noises when the injector seals go but I'm not sure, and that is usually on e85 though. Just something to rule out.

 

I appreciate your guys advice thank you

 

ok so here is an update i still have no clue whats going on. i re-timed the engine. installed new coils all the rockers and lash adjusters seem fine nothing seems loose. has new plug again. engine is still running like crap and missing big time. only thing i haven't checked yet are the injectors. what do you think the odds of it being those being bad at this point and does anyone know if there is a way to pin them out or anything? starting to really suck

 

Since I didn't see anything directly about it, have tou checked your intake valves yet?

 

for carbon build up? the steams looked ok, but i couldn't get a super good look at them. also forgot to say i did compression on the engine as well all 4 cylinders are around 210 psi (1447 kpa) i know stock i think they were getting 1500 kpa compression. but what exactly should i look at in the intake valves? just black carbon on the steams? and would sea foam clean them up