I just installed a new long block in my 97 z m6. I have 35 miles on the engine but i keep getting a random misfire code. The car is bone stock except slp loudmouth. The plugs, wires, coil, opti, ckp sensor, and egr valve are all brand new. The ICM tested good at autozone. The car starts right up, never hesitates, and runs strong. I need the problem to be fixed so I can pass emissions in TN. Also, I have checked all plug wires and there is no arcing.

 

Find someone with a scanner with "GM enhanced parameters". They can recall the misfire count by specific cylinder. That might provide a clue where to look. Maybe a cracked spark plug insulator, a plug wire that's loose or got nicked during install, faulty injector, etc.

 

Ok i will try that. do you know if oreilly autoparts or autozone uses a scanner with gm enhanced parameters?