Last week my 94 Z began cutting out while under a load. It started out of no where. It sat for about 2 days. I got to start it, and it backfires through the exaust and idles rough and surges to 1400rpm then back down to 700rpm them back up. When I get the car going and give it a decent amount of throttle to get it going it cuts in and out. It will continue to run, cutting in and out, and backfiring. While standing behind the car when it is running there is a strong smell of gas. So for the past 3 days I have put new plugs, wires, and oxygen sensors in it. I start it up and it idles fine. Once i get it out on the road it does the exact same thing....cutting in and out, idleing rough, but not as rough. I take it home and shut it off and it will not restart. I give it a shot of WD-40 into the intake and it fires right up and idles rough but will stay running rough. I don't know where to go next. I really don't wanna through anymore money at it unless I can get an idea of what the problem may be. I called two chevy dealers. They would not tell me much of course, but one said it may be the fuel pump, and regulator, and the other said it may be the opti-spark. The car has 69K on it and a few bolts ons. Has anyone had a simmilar problem, or may know where to start. Any help would be appreciated. Thanks

 

Sounds more like the fuel pump. Not sure without looking at it. Next time it wont start. Kick or hit the fuel tank. See if it will start. I know your thinking WTF. But try it. Unless you have a fuel pressure gauge. Theat will tell you if its a fuel problem. and the sympton does sound like it could be the opti. But when you said you spray it and it starts. Sounds more like a fuel delivery problem.. Hope this helps.

 

Sounds like your opti more than your fuel pump. If your exhaust smells bad, then your running rich (i.e., not burning all the fuel in one or more cylinders, due to weak spark from the opti). Mine did the same exact thing as you describe.

Swapped out the opti for a new one, and runs like a raped ape.

 

OPTI!!!!!!!

 

i missed that part about running rich.

 

Ya, I was kind of leaning towards the opti too, cause you could probably put two buckets at the exaust and get raw gas out of it, thats how bad it smelled. I don't know how I could have a fuel problem?? I just might have to suck it up and buy a new opti for it. Thanks for all the help!!

 

Its the OPTI more than likely. My Opti went bad and it started with irratic idle and backfiring and got worse with higher RPMS. I also had a heavy fuel small from exhaust. Opti was what fixed mine.

GL!