Cavtrooper

Strange problem. When you turn the key on you can hear the fuel pump running. If it shuts off after a few seconds the truck will start right up. But, if it stays running the truck will not start. it is an intermittent problem that is driving me crazy.
I have swapped out the ECM with a known good.
Swapped out the distributor with a known good.
New EEC relay.
Checked conections, grounds.

I am at an end, can anyone give me some help?

Green '01

Have you checked the fuel pump? In your post, you said if the pump keeps running, the engine won't start...I assume it turns over, but won't fire. Sounds as if the pump is trying to prime (pressurize) the fuel line but keeps runnig because it isn't moving fuel. If it was a clogged filter, the pump would experience enough back-pressure to burn up the pump (like mine did). Maybe the pump isn't moving fuel at all on occasion, allowing it to continuously run trying to build pressure, and isn't enough to fire up the engine.
Just my $.02
Good luck.

Kphyle

it may be the fuel pressure regulator. it may be built in to the fuel pump, I'm not sure, just got into the ford scene this week. I had that problem with my chrysler sebring. I had to turn the car to the on position, let the Fuel pump run for like 15/20 seconds then it would start. then whenever the fuel pump didnt come on, id have to try it again. then sometimes it started regularly.

just thought I'd help