ok i have a 94 camaro z28 moroso cool air intake bbk 52mm throttle body everything else pretty much stock, hollowed out cats.

Ok so at idle the car just started making a noise and i was thinking it was a back fire but its wierd its not loud and it really sounds like the exhaust is sucking air in. it only does it after the car is hot.

The other thing its doing is when it warms up and you mash the gas it starts miss firing or something it loses all power and starts at lower rpms it has bad vibrations.

I had 2 codes one was a evap purge valve malfunction, and i cant remember the other. but i my boss told me they wouldnt effect my drive ability. i cleared the codes and only the evap code came back. i replaced the valve no luck on fixing it.

just figured i should add the fact that i did fuel pump fuel filter opti water pump radiator a lil more then 6 months ago.