i have this 93 z28 camaro that sputters and backfires but doesnt do it all the time. ive changed the coil pack and have put some injector cleaner through. anybody have any ideas whats going on with it?

 

Probably the OPTI.... Is it throwing any codes??? My 93Z didn't when it was bad...

 

Under exactly what operating conditions does it sputter and backfire? By backfire, you you mean a popping in the exhaust, a real "backfire" through the intake manifold, or simply misfires? High RPM, low RPM, under load, at idle, all of the above?

Is when it happens or doesn't happen tied to high of low engine operating temperatures? .... damp weather? ....totally random?

Does your engine have any modifications? Have you scanned it for codes? Have you checked the fuel pressure? Have you run it in the dark and looked for arcing wires, coil, etc? Has the coil, IC module, Optispark distributor, plugs or wires ever been replaced? If so, how old are they?

 

well i just got it back from the shop and the guy there said its the fuel pump going bad cuz my pressure is only running a 22. only problem is its 500 bucks to fix it because you have to drop the exhaust and rear end to even get to the tank, is it possible to access the tank by cutting into the trunk?

 

Go to the Fuel & Ignition forum. There is a "sticky" at the top of the forum topic listing, with links to "how to" replace the fuel pump by cutting a "hatch".