5.9 Magnum help needed

check the fuel pump emergency shut off, sometimes they trip for no reason,

THIS and before you tear the truck apart throwing a fuel pump at it, see if you can get a manual/ wiring diagram. Check for pump power, and all vehicles I'm aware of usually have a PUMP RELAY which can go bad. Look around under the hood as well as inside for a pump relay and pump fuse.

I.E. CHECK FOR POWER at the pump.