Sometimes an old and very used ignition coil and/or condensor can cause this problem. I was experiencing this same type problem about three years ago. I would get in my car after it had been sitting for days and fire it right up, then drive it at full temperature for 15 minutes or more, park it, go into a store or whatever, come back out and try to start the car. It would crank and crank and crank, but no start. Got some advice from someone about checking the condensor and coil. I just replaced them. Problem went away.

Deluxe