6.5 L Starts, quits after 2 min. won't restart
 

1998 6.5 L Chev. When I go to start it from cold, I wait till the wait light goes out, hit the key and it starts immediately (no smoke, runs crisp). It may run for 2 minutes then quit like someone turned off the key. Sometimes it wont restart. If I wait long enough it will start. Driving it for 10 minutes yesterday, it quit 3-4 times will driving at 40mph. I put it in neutral and it restarted each time.

Today, it started instantly,, ran for 2 minutes, quit, wouldnt restart. I waited 30 minutes, it started instantly and ran for 2 minutes and just now quit. AND it wont start. I've gone thru this scenario dozens of times. I dont know what to look for. Any ideas?

(for some background, i've replaced fuel filter,, when i turn on the key and open the bleed knob on top of the filter, it spews out fuel.)

Thanks,
allan