I have been away from 5.0s for a while, but recently purchased a 92 Limited edition Convert with 5.0/ AOD and 60,000 original miles for my daughter. Other than the battery and tires it was 100% stock. I had a Mustang Shop in Dallas install a New Old Stock GT40 upper and lower intake, injectors, 1.7 roller rockers, 73 mm MAF and 70 mm throttle body so the car would be ready for her birthday. At first they installed 30# injectors (thinking ahead for the Vortech!), but it ran so rich at idle they suggested changing them out to 24#. Now that I have the car back, it starts and runs ok when cold, (although I think there is a vacuum leak since the car whistles when it shuts off), but once you shut off the car with the key it will not restart until it cools off 20-30 mins. It never dies while running, just won't restart. I took it back and they replaced the distributor module, ( which they said usually fails when it gets hot and causes the car to die), which made no difference. There is 38 psi fuel at the rails when it fails to restart. The spark looks a little yellow when you ground a plug and turn over the engine. There are not check engine codes stored or pending in the computer. The car has left her stranded now so much she doesn't want to drive it, and I am going broke towing it back to Dallas. Any ideas of things I could check? I am about ready to replace all the parts back to stock, or put it up for sale. Thanks