when you turn the key to the "on" position, the lift pump will cycle only a few seconds. For a fuel filter change, you want it to run longer, like 25 seconds (or even longer). You can make it do this by turning the key to the "on" position, letting the pump cycle, then turning the key to the "start" position just long enough to energize the starter, but not long enough for the engine to turn over and start. Let the key return to the "on" position as if you had actually started the vehicle. The lift pump will run for around 25 seconds. Lather, rinse, repeat as necessary.
If the canister isn't full, the truck will die when you try to start it. Once fuel (or air) is in the canister, there's only one way out--through the VP (okay, okay, you CAN open the drain... . ). That means if you have air in the canister when you fire it up, eventually the air is going to go through the VP. Some of it will go harmlessly back through the return line; some of it will get stuck in your injector lines. That's when you have a fun time bleeding fuel lines.
By cycling the pump several times, you let the lift pump purge the air from the canister, letting it flow through the VP and back into the tank via the return line, not into your injectors.
--J