Idle...lower Idle...dies

[nvr2fast4me]

I turn my car on, it jumps up to 1k RPMs...almost instantly it will go straight back down and die. Now...this is about 3/4ths of the time i start my car. The rest of the time it will start and go up to 1K RPMs then drops down to 400 RPMs sometimes even lower...and THEN it dies.
This only happens when i start the car up and touch nothing (in which its SUPPOSED to run normal, am i right?) but if i supply a small amount of gas and keep the rpms up it will stay alive.

Also, this doesnt just happen when i start my car, it also happens when i shift in to neutral while in motion. This has been happenin for a lil while now and ive gotten used to havin my right foot constantly on the gas so it doesnt die, and my left foot for clutch and then breaks.

I was told it could possibly be my Idle Air Control Valve on the intake manifold...but i dont know, it almost feels like im venting into the atmosphere and dying.

What do you guys think? I wanna know all possibilities of what could be wrong. Every thought of what it might be. Also, what i could do to go about fixing this.

1990 GST

[DSM614]

sound's like your car is creating a lean condition at start-up...

Look for disconnected hoses, big crack's in hoses... your emmision's should be gone by now.

Check your afc setting's because idle air/fuel will always be a critical adjustment.

Maybe your fuel pump?

[biglipps66]

I assume you havent touched anything and this started happening..

What kind of vac are you getting when it starts?? High or low? Can you hear any vac leaks anywhere? Have you recently done anything to the car.

idle air control in on the TB not the intake mani :) Ask JP about disabling his cold start feature... his car doesnt idle for a minute and he has to give it gas :) But all better for a cooler TB.

[nvr2fast4me]

Sorry i didnt reply in a while, been too busy.

I thought it could be the fuel pump but it appears to be fine.

As for cracks in the hoses, I've been looking for one forever because of the major boost leak. The best possibility we came up with was the seals on the inside of the turbo were cracked or sumthin, because the only hissing noise we heard (when we put compressed air into the intake side of the turbo while checking for leaks) seemed to be coming from the turbo itself.
Also, dont have an afc.

None of this stuff started happening until i installed the MBC. I did disconnect the hose runing to the Waste Gate because my turbo was still releasing at 14 lbs.

[Puckplaya]

I had a similar problem... it could be you ignition module in the ECU... thats what the problem was on my 98 gst! once i started the car it would idle at like 200rpm... then i adjusted the idle control to let the car run but it was no use... i thought it would be the spark plugs,battery, and even the alternator in which i replaced all of them but it still idled low... later i found that it was the ignition module in my ecu so i had it replaced and now its fine