My 95 did the same thing. Was the PIP in the distributor which fried the coil. New coil would make it run for about 50 miles before it ate itself again. New PIP (or new dizzy) and a new coil fixed it right up. The distributors in these cars are notorious for going out, if you pull the cap off and see a bunch of silvery powder down inside it that is likely the culprit. A rebuilt stock replacement from Napa/Autozone or wherever is fine, just make sure you save the receipt in case you get a dud. Don't buy any MSD products. Also MSD is bankrupt which is lol worthy.
2000 Mustang GT Steeda build #48. Bolt ons, suspension, Novi 2000.
Just because I give you advice, doesn't mean I know more than you. Its just means I've done more stupid ****.