What causes the fuel pump relay to loose power and after a while it regains power?
My Pick up dies out and if I turn off the switch and turn it back I hear the fuel pump start pumping and then the truck will start an run good for a long time until the relay stops againg.
Have you replaced the relay. Might not sound right but try it anyway if you have not yet.
I think that many of the relays are identical for this truck, so you can switch the fuel relay for another identical relay and see if the problem is solved - try the relay for the rear window defogger, not the headlights, so you don’t loose the headlights while driving. Then you will know if you need to buy another relay. Let us know what works in case this happens on my Silverado.