I bought a 96 Z28 a few months back and the service engine soon light was on. The car already had aftermarket exhaust so I figured this would probably be the reason the light was on. Sure enough after a trip to advance to pull the codes my theory was correct. Whomever had the car before me took the cat. off. I've heard different methods of fixing this but I've never seen any of them work. So I was wondering if anyone else has fixed this problem (other than ordering a new catalytic converter).

 

Reprogramming the PCM or installing O2 simms will turn the light off.