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1992 LT1 with misfire and backfire, no power when given gas, after replacing ignition control module (AC Delco), ignition coil (MSD 8226), MSD Optispark, spark plugs, plug wires and cats removed because they were clogged. Fuel pressure is good across the board as well as spark. What could be the problem? Please help!
Its my first Corvette and I love it! 1992 C4 Corvette Convertible LT1 in Black Rose Metallic and Black interior.
Last edited by 6stiffy9; Jun 24, 2025 at 09:31 PM.
Reason: Added pic and better explanation of problem
MSD has not been good to me in my experience. Especially when mixed with GM control modules. No optispark expedience but coils and control boxes that would burn up factory ignition control modules incessantly.
Look under the driver side dash for this.....IGNORE THE LETTERING IN THIS PIC.
FWIW I'm having a similar problem with my '93 C4 and it hasn't thrown up any fault codes. I cleaned the MAP sensor with some sensor cleaner and that improved the rough running a little. Mine starts and runs okay until it warms up and it seems to run okay on full throttle.
Last edited by Haggisbash; Jun 25, 2025 at 11:23 PM.
Im 99.9% sure the wires are correct. Thanks for the compliment! Its such a beautiful lady that I just have to get her back to her former glory. Her name is Purple Haze lol.
Un-plug the Mass Air Sensor. It will run rich as a pig but if it starts and runs you may have found your problem. Please update us with you progress including the eventual successful repair so others will be helped.
I will do that. Unfortunately its been about a week since I was last able to work on it but will be trying multiple things this weekend, hopefully finding a solution for that beautiful lady.
Help! At a dead end!
