2000 f150 4.2 starting problems
 

I have a 4.2l f150 (2000) manual tranny, anyhow when cold starting or running the truck everything is great, no hesitation or idling problems, but starting after being just shut off the fuel pump does not kick in all the time. I can turn the key several times until i hear the fuel pump engage and all is fine. There were two relays the same in the engine compartment fuse box so i switched them to see if that was the issue and it wasn't. also i hear a loud click when the fuel pump doesn't engage (from the engine compartment) leading me to believe the problem isn't the fuel pump, but the relay or something else under the hood. any ideas would be greatly appreciated thanks!!!