Hi I have a 1987 Mustang GT and am continually running into a problem of the engine dying. I have tested and replace the battery, tested the starter and alternator and replaced the plugs and wires. For laughs I put a KNOWN good battery from anothertruck (V8 Ram Hemi)and it did turn over. I let it idle and revved it a fewminutes with no problem. I went to the bathroom after it was idling for a few minutes and when I came out it was off. I tried to turn it over and nothing, it acted like it didnt have the juice. I put the battery back into the Ram and the truck turned over fine. Please help me as I am trying to get this car running right and plan on dong ALOT to resto it, it has sentimental value to it.

 

Starter wouldn't cause a car to die after it's starting. It would prevent it from running.

Bad battery would't prevent a car from running after it's already started unless the alternator was bad.

Fuel delivery sounds like the issue. Common issue with carbed cars is Vapor Lock. Basically if the fuel line is running bysomething that causes a hot spot, the fuel itself gets vaporized in the line. This vapor stays trapped in a part of the fuel line or the carb itself and 'locks' the fuel from flowing.

Starving the car and killing the engine. I'm guess that after a few minutes (15-20 or maybe a little less)of cooling down it starts right back up!?
Could also be the TFI module. The electronic ignition module that's directly attached to the Distributor. It would give similar issues as when it overheats it will cause the car to shut off. Ford had a recall for that item specifically (Engine dying after warmed up at unspecified intervals) Don't remember where to find the fix for that.

 

Thoght of that and admit I prolly should have added in that it is a 302 EFI. I used to have that issue on my moms old asz 84 Sentra. Fuel Pump maybe, Ive replaced it before but it was a good while back. On the bright side I am restoring this beast. Pulling everything out and going to end up running it off of a stand so that will clear alot up. Cant wait to work out the bugs and add some 185 AFR's with a 331 Stroker and some other goodies.

If there is anything else anyone can think of, the help would be most apreciated. Thanks again for the info.