89 4.0 cutting out while driving

While driving the other day the engine just cut out and died.
After a few minutes (5-10) she started back up for about a mile and did it again. Once again after several minutes I made back to work. I replace the in-line fuel filter at work and let her rest.
I got home w/ no problem. The next day almost made it to work and it all happened again.
When the engine is cold it runs for quite a while 15-20 min. till warmed up. Once warm it shuts off- no studdering or warning.
After it cools 5-10 min it will start again and run a mile or two and do it again.
I also replace fuel filter sock in tank as well.
Every time I turn the key I can hear the fuel pump prime and pump and I have checked the fuel pressure release after cranking even when she won't start and it has pressure and fuel. When I leave the hood up it stays cool enough and keeps running.
I have done no modifications and this started out of the blue?
I have a new fuel pump to put in (OEM) but this one seems to be working fine. It almost sounds like vapor lock but I can't think of anything that would be causing it.
It seems to be engine heat related.
Any ideas?
Thanks
Mike

First thing to check is the CPS (crankshaft position sensor). This is located near the top of the bell housing with its connector being back near the MAP sensor. When you experience the problem, disconnect and reconnect the CPS connector. If that cures it, then you've identified the problem. Most folks will then replace the CPS but a few others have just rebuilt the connectors.

CPS

I second PaulJ- you've ruled out fuel so maybe its spark. I had a similar problem and the CPS fixed it. Vapor lock is impossible at the pressures your MPI fuel pump delivers.