Are you talking about the pickup coil in the distributor? Is that something that can be bad and only fail when car is warm and has run for a while. The restarting the car when hot and having no spark has been a solid symptom for a while.
I agree with tooljunkie, I had a 1990 318 Dodge D-150 that had these very same symptoms. Truck would run and then for no reason die. I'd wait just a little while and it would crank up. Wound up being the pick up in the distributor.