Alright first the info:

09 Cobalt SS 18,900 miles on it.
Been Trifecta tuned since 600 miles (23psi select a tune) So I'm not always driving in tuned mode.
Always use Shell 93 gas.

So the problem is while I'm driving with the tune activated when I'm going into full boost say like 2nd gear and let off the car back fires bad and kind of goes into limp mode for a few seconds. No CELs and the DIC does not flash anything when this happens. I have had the codes p2270 and p2232 both pertaining to the rear 02 sensor (I have a ZZP downpipe with high flow cat and angled bung). Also when the car does do the limp mode it changes exhaust note to a suburish sound. Then the car just goes right back to normal running fine sounding fine. It does not do this every time I full boost though. I have been told it could be my wb02 going bad and I have been reading threads about it but it seems people having trouble with it also have idling problems, which I really haven't noticed any issues with mine.

So do you guys think it's the wb02 going out? I don't know why it would be the tune since I haven't changed anything on it and this has just started happening recently.

 

not the tune. Its been running fine and no changes were made to cause a problem. It could be a front and or rear o2 sensor problem. O2s do some wierd things when they start to go out..