ok so about a week ago i changed the muffler on my 92 eg si hatch and now when the car warms up i get a backfire from 1st to 2nd and 2nd to 3rd, before it wasnt doing this to my knowledge, would the muffler have anything to do with this??

 

If you got the cat back system maybe the gaskets arnt hooked up right? From the racing headers to the exaust manafold

 

so you get backfire ? Out of the intake manifold? or After fire coming out of the exhaust?

 

i got the whole system but i had to order a test pipe, so only the muffler is on cuz my old one was rusted out, and it sounds like its the "after fire" your talking about

 

then in that case the exhaust has nothing to do with it..... sounds like too much fuel... maybe a leaky or bad injector? Or bad cat

 

my brother said it might be something with the ignition cuz he had the same prob with his camaro