90sleper

Ongoing issue with my car dying when stopping. I had this issue years ago when I originally purchased the car, had it 'tuned', sold the car, previous owner had it at the track a few times then sat for 3 years, then I bought it back. I don't have many details of what happened with the car in the few years I didn't have it.

So, the problem is back. After I had it tuned when I originally bought it, the car ran fine. I took it to the guy that had been working on the car to get it track worthy and he said it was a vacuum leak. 'Repaired' that but didn't get but a few miles down the road and still doing it. Took it back then found the heater core was shot. Knowing that wouldn't be causing the issue, I took it to a performance shop to get the core replaced and have them check out the stalling issue. They said car was done. Talked to the mechanic about the issue and he told me he just noticed(after putting everything back together) that there was a tear in the egr valve diaphragm. Um..not sure why they didn't just replace it but whatever. Said that might have something to do with it. Took it home...still stalling. Replaced the egr valve....still stalling.

Sorry for the long story, but more detail the better usually.

As far as the actual stalling....After driving for a few minutes and I let off the throttle anywhere above 1100 rpm...it dies. (so not necessarily coming up to a stop). If I baby the rpms down to idle using clutch/throttle, it will sit at idle all day long. But bump the throttle up and let it drop....it dies.

Seems both mechanics have no idea what the problem is and I am having a hard time finding what could be wrong surfing the net.

Thanks in advance for any feedback.


'90 Mustang LX Convertible ('7-up')
5.0 with TrickFlow and Vortec Supercharger

90sleper

Tried new IAC valve...didn't change.