alright heres my dillema. yesterday while driving my car it misfired. later on in the evening it stumbled again then quit. so this morning i went to carquest picked up a coil to see if it would run. i swapped coils and it fired right up.i was happy and headed home. tonight on my way to the pub it stumbled and quit again so i towed it home. now i dont know what it is. it seems when the car gets hot it quits. is the fuel pump fried or the optispark or the ICM. I need help ASAP

 

check the postive battery cable right near the ac compressor. Alomost the same thing happend too me on my 94 Z. the cable touched the clutch and it would hessitate and every now and then die, I took me two month too find the issue.

PS I replaced the coil first to.

 

Is it raining out?

 

Test fuel pressure and spark when it won't start.

 

na its not raining. how would i check fuel pressure, what would i need

 

fuel pressure gauge, you hook it up to the schrader valve on the back of the fuel rail.

 

when it dies, do the gauges all shut off, all your lights? does it smell like fuel?

 

fuel pressure is good, code reader didnt bring up anything wrong just kept flashing 12.yes everything shuts off and smells of fuel

 

yeah. if everything turns off, then a ground or something is loose.

 

okay nevermind about the lights turning off..they stay on

 

if i let the car sit for an hour or so it fires uo and runs mint for 20mins the coughs and sputter at 4500 then to 3000 then 1500 then it quits the whole time it runs the fuel pressure is at 38psi then 42psi when the motors off. this is my daily driver and i need it back on the road. i dont know if i should buy an optispark or a msd 6al first to get it going

 

My car does the same thing, I'm about to kill it.

 

Change the fuel filter (My fav response to spitting and sputtering threads)

 

im thinking i should just pull the motor and put a carb in it

 

That would be cool. I kinda miss the carb'd 350 I had in my 83 Z28.
Are you running a 6al now? If so just take it out and see if it runs normal. I tried this when my car was running like garbage. I had a 6a, took it out, made no difference to the problem, reinstalled it after figuring out the inside of my opti was a rusted disc of garbage.

 

I would replace the ignition module. I had the same thing happen to me few years ago, it would idle for about 15 mins and die. So, I replaced the module and it fixed the problem.

 

get a test light and check the voltage at each injector, wait till the car is warm (or at the temp where it has missed in the past week) if everything is firing, check the spark plugs, and plug wires. How many miles are on the opti? And have you done anything to your valve train, when i changed cams i didnt properly adjust my rockers and after a week one cam loose, took me a month to figure it out. Check maf, by having the car run and tap it w/ the butt of a hammer, if it stumbles bad maf. Keep posting and don't get fed up, these cars are a pita but you'll get it. let us know


"Is it raining?" what are you f*(*king retarded?

 

oh and going from fuel injected to carbed is a total headache, and requires alot more than a carb and new manifold.... believe me, i've done it before (thankfully not on my car)

 

also you might wanna try the icm relocation mod... it's free and it takes some heat off your icm.

 

ignition module, seen it before on many gm cars that ran good untill they got hot....