Yup, was a PITA trying to find out what it was though. Best part too was that I just bought the truck and drove it out of this guys driveway and about 2 hours later it dies and wouldn't start. Didn't have fuel, nothing back there, so I bought a fuel pump on the way home from work, and luckily figured I'd try to see if there was power back there for the pump, and saw it wasn't getting power.
Took the pump back...
I didn't know what to do at that point, I check fuses and wires etc, thinking something electrical went.
Decided to see if I was getting spark, and I wasn't getting that either. Decided it was the cps (crank position sensor).
Bought one of those, and when I was about to install it, it dawned on me that it couldn't be that, because it wouldn't cut fuel when you turn the key on (when it normally 'primes' the fuel pump). As even if the sensor was bad, when the engine is stopped (as in, before you turn the key to start, having it in the on position) it doesn't relay anything to the pcm anyway, so it wouldn't matter.
Decided to get pcm ordered.
Whats odd though, is it was on/off a few times. Twice it randomly started, we thought it was just a loose wire or connection somewhere from messing in the engine bay. It would run like a champ, and then come out of the store and it wouldn't start.
Put the new pcm in and she started right up though. No problems since