I just had the same problem. If you pull the fuel pump (or lift pump..same thing) plug one end and suck on the other, then plug the hole you sucked on with your tounge and see if it holds a vacuum. If it does not, there's your problem. If it does, re-install (carefull of the push-rod...grease holds it in place well). After you install, you can check fuel flow with a hand vacuum pump like a break bleader:
1. Pull the outlet line from the fuel filter housing (the top hose on the right side of the filter housing) and be sure the vent on top is closed.
2. Connect your hand pump to the metal line comming from the filter housing (this will be easier if you have pre-filled your filter with fuel)
3. Pump until you get fuel with minimal bubbles through the hand pump.
4. Quickly, disconnect the hand pump and reconnect the fuel line to the outlet.
5. Per the tech manuals, bleed the system.
a. Batteries connected
b. Pink wire to injector pump disconnected
c. top vent on filter housing open
d. run a line from the port beneath the vent (top left of filter housing) to a water bottle (something clear) and put it under a windshield wiper or on the hood so you can see it from the driver's seat.
e. turn the truck over for 15-20 seconds...repeat this with a few minutes in between cranks (to save your starter) until you see fuel flow into the bottle.
f. after fuel is flowing, cap the vent, connect your pink injector pump wire and fire it up!
It will choke and cough at first as the air works its way out. If it dies, start it up again....let it run for 10-15 minutes and you should be good to go.
Good luck!