computer or injector issue?

[jppasta]

I have a 2012 Camaro SS coupe, everything is factory except i put on a CAI air intake... recently on a hot day I left work made it up the road aways and stopped at a stop sign went to take off and the car died. I restarted it and sounded like it was only running on 4 cylinders or so... I called the GM garage for them to come get it. I rolled it back down the hill into my parking lot. Waited for them to come get it. While in the time i was waiting I tried it and started and ran fine... I still had them take it in to check it out.

They came back said there was some mis-fire codes on the computer but couldn't tell which cylinders... I told them that when it was having issues they stabilitrack and other warning lights where popping up on the dash. They claim that the aftermarket air intake could be causing this issue... but at the moment it was running fine.

They call me back later say something didn't sound right and looks like my cats are plugged... ok not sure how that happens on a car with 3500 miles but ok...

so parts come in they changed them out yesterday and now it's running rough again... They way it's acting i'm thinking its a bad ground somewhere in the wiring? asked them to check it, other than that I'm out of ideas, surely if it was bad gas it wouldn't be doing this would it? i'm been running premium which is hard to find anymore and not sure alot of people use it so i can see it being older fuel... any help please?? it's almost been 2 weeks without the car and I'm getting frustrated and irratated with the dealership