My Mustang 5.0 has stalled out once last year and again recently. Same situation. I drove it for 300 miles with stops about every hour and a half. Pushed to to 90 MPH at times. Ran fine other times on the road for more than two hours. But all of a sudden the engine dies. Electrical all works but won’t turn over. If I sit in it for about 10 minutes, it will start and run for the next 5 to 10 minutes than a cough or two and pull over. I have had new plugs put in and also replaced the whole distributor. Ford mechanics have stared at it and scratched their heads and say it is running fine when they hand it back to me. Does anyone have a solution??
Did the new distributor include a new ignition module? http://www.rockauto.com/catalog/moreinfo.php?pk=1006185&cc=1133929
If you have not replaced the ignition control module on the side of the distributor that can be the problem. These failures can be related to heat. I have an 89 GT and replaced mine twice. Very easy to do. They sell a removal tool to get the 2 screws removed from the module…I carry an extra one at all times takes 15 minutes to do on the side of the road.
Carry a thin marker with you and mark where the distributor shaft was in relation to the block drawing a straight line. Loosen the distributor bolt and turn the distributor it so you can access the screws and remove ( the module drops toward the bottom ) after removing the connector . Make sure you apply the heat sink grease and intstall the new one These modules run very hot… Now turn the distributor and align up the marks you made with the dist and intake and tighten down the dist bolt to put your timing back and start her up.
These modules can an act in strange ways…will go for days then die, and then start up the next morning or if you shut the engine down for a few then will not restart…
Watch your tach while cranking, if the tach does not move some ( 100-200 rpm ) when it won’t start thats your problem. These cars are very simple to diagnose.