Crank, No-Start Problem

I have seen this question asked a lot on here but have yet to see an answer
to my dilemma. I bought this vehicle used a few months back and the
problem started about a month into my ownership. The problem started while
sitting idle with the vehicle in park. The truck just died on its own. There was
no indication of a problem. I tried restarting it but it would only crank. The gas
gauged showed to be empty but I know there was over a quarter of a tank of
gas left. I had the truck towed home and started troubleshooting/researching
the problem. Here is a list of things I have changed trying to resolve this
issue with success thus far:
1) checked fuses and relays - no problems here
2) replaced fuel pump
3) replaced air intake control valve and an exhaustive cleaning of the air
intake
4) removed an aftermarket security system (wasn't using it anyway)
5) replaced battery and connections (this really needed to be done anyway)
6) traced electrical connections for the fuel pump to see if anything looked
bad
7) had a friend good with electrical things check everything out electrically -
determined (as far as we could tell) that the tipm was bad
8) bought a used tipm and replaced it
After all of these things, the truck would start and then not start. The problem
got worse and more intermittent. At one point, before replacing the tipm, I
was able to get home by pulling the fuel pump relay and providing
continuous power to the fuel pump with a jump wire. The tipm was replaced
this evening and the truck started right up but died after about 10 minutes
after just sitting idle.

As you can imagine, I am at my wits end. I don't know what else to check or
fix. Does anyone have any idea as to what is going on?