I need help. I have banged my head against the wall on this one...I traded for a 1996 Mustang converted to a Cobra SVT from a V6. I think the drivetrain is out of a 98. I try to start it and it cranks over and dies. But if I put my foot on the gas pedal to raise the idle, it runs smooth. I let off the gas pedal, it dies. Any ideas?

 

When was the last time the fuel pump or fuel filter were replaced?

Testing the throttle position sensor may also be a good thing to do.

 

Thank you for replying. I can't fiure this out at all. So any suggestions are helpful and appreciated.
I haven't checked those. I would think the fuel pump is working cause using the gas pedal keeps the car running. However, I hadn't thought about the throttle position sensor. I'm not used to messing with newer stuff, only older stuff like 70's and back.
I borrowed a computer from my friend and it read out 2 codes, p1000 and p1260. The second, P1260, says theft detected, engine disabled. But if that was the case, it wouldn't run at all, logically.
The first code, p1000, spit out a bunch of incompletes (cycle test not complete).
I wondered if it was the Idle Air Control Valve (IAC Valve). But again, ?????
I hate newer stuff, lol.

 

Sounds to me like a possilbe vacuum leak. Keeping your foot in the throttle is dumping more gas instead of leaning it out to the point of stall. Poke your head around while at the lowest rmp sustainable and listen for a sucking sound. Check all the vac lines around the intake/TB and be sure there are no cracks. May also want to check plugs/wires if you feel it is misfiring. But if it runs decently smooth while your foot is in it, I'm guessing a vac leak.

 

I checked around for any vacuum leaks...none that I could find. Keep the ideas coming.

 

I had this problem with my 00 GT. It would start then the RPM would drop and it'll just die out. Pushing the gas pedal will keep it from dying but as soon as I let go it will die. I replaced the IAC and it never happened again. I bought the IAC for about $50. I'm not sure how much it'll cost for you though.

 

That's what I've been thinking (IAC valve). Or a sensor of some sort. I'm just skeptical of buying anything and it not work. I guess yours is cheaper by a few bucks. I'm thinking of going ahead and getting the IAC and trying it first. Hearing someone else that had the same problem, and fix, makes me a little more comfortable with taking the chance. Thanks.

 

You're welcome! I hope that fixes your problem!!