i just got a 1997 z28 with a six speed. the motor is an lt1 with a k&n cold air kit. the dude i got it from took the old exaust off of it and put a factory muffler and added the cat.s back on it. he said about a few days later it started to mis a little bit and pop back. to me it kind of sounds like it is poping threw the exaust. could this be caused by adding the cats back to it and putting on a factory muffler man muffler to it? could the computer be programed to run without the cats and got messed up from the cats being put back on

 

Wrong forum.... not an Advanced Tech question. I'll move it to "LT1 Based Engine Tech" for you.

 

your o2 sensors are prolly burnt it will cause a idle miss and for the car to run rich

 

Does it just do it cold? Its normal for it to sometimes pop in the exhaust with the engine/cats cold if you rev it a bit.