Im thinking maybe that's the problem Stewie. But if you would please check out my other post ( shuts off at 65 mph) please , and see what you think.

 

It takes 2 minutes to check the fuel pump for proper function. I would cancel that order and rent a fuel pressure gauge from an auto parts store, costs ~$100 that will be refunded when you return it. Hook the gauge up to the fuel rail, and start the truck; should hold 49psi +/- 5psi.

Did you determine what your missing when the truck dies? fuel or spark? I would be leaning towards spark.