GT A beast at WOT, but barely hanging on at idle...

dubbsix · May 4, 2009

My 94GT is throwing me for a serious loop. When i bought it i noticed it had a weird idle stumple that seemed completely random. When i popped the hood i replaced:

Plugs/wires, cap/rotor, new spark plugs, new air filter, clean the maf.

I put a pressure gauge on the fuel rail and found that with the key on and the engine OFF the pressure was 37PSI with no bleed down. When i started the car the pressure dropped to 32PSI and went up everytime i goosed the throttle.

Seems completely random, no codes and no part throttle or WOT performance issues. Has anyone experienced anything similar? My next steps are:

Fuel filter replacement, try cleaning the IAC. HELP!

ram360 · May 4, 2009

idle stumble??? You mean it surges? won't idle at all? idles low? I'd replace the fuel filter regardless. It's cheap and who knows when it was ever replaced. Did you try to reset your base idle?

dubbsix · May 4, 2009

ram360 said:
idle stumble??? You mean it surges? won't idle at all? idles low? I'd replace the fuel filter regardless. It's cheap and who knows when it was ever replaced. Did you try to reset your base idle?

The car will idle, but the rpm's drop randomly and you can see/feel and here the engine "stumble" when its idling. Anyone know what the running PSI should be for the fuel systems?

ram360 · May 4, 2009

stick or auto?

dubbsix · May 4, 2009

Its 5 speed.

Lwiss · May 5, 2009

I have the exact same problem and would like to know more before replacing all you replaced because that's what I wanted to replace before reading this thread.