I have a 94 Z28 Convt. A while ago the car just died on me. Took it into the mechanic and he replaced the opti with an O-reilly brand twice. The car still wouldn't run smooth. So the mechanic swapped computers thinking that was the issue. Bingo car ran great...until you shut it back off. Then it wouldn't start back up. It was now throwing a High Resolution code??....We ended up putting a Delco GM opti in it and now it will not run at all.....It will however run with the o-reilly opti until its shut off and restarted....Any Suggestions????

 

are you getting power to the coil when it doesnt start? pink wire.

 

see if any of this helps.

 

Also could be the wire harness to the opti or the ECM, check craby above.