To check electric fuel pump pressure in a Ford F150 pickup, test the engine with starter fluid, connect a fuel pressure gauge to the Schrader valve, have a helper crank the engine, and look at the reading on the gauge. This method works for the Ford 4.9-, 5.0- and 5.8-liter engines.
Remove the air duct intake hose from the throttle body, spray starter fluid down the throttle body, and quickly reattach the hose. Have your helper crank the engine. If it starts and runs for a few seconds and then dies, there is a problem with the fuel pump, and you must replace it. If it won't start at all, there may be other issues involved, and a further pressure check is needed.
Locate the Schrader valve on the fuel injector rail. The Schader valve looks like the valve stem on a tire. Unscrew the cap, and attach a fuel pressure gauge. Have your helper crank the engine again, and watch for movement on the gauge. If the gauge registers between 45 and 60 pounds per square inch on the 4.9-liter engine, the fuel pump is fine. The correct reading for the 5.0- and 5.8-liter engine is between 35 and 45 PSI.
If the pressure is okay, there is another problem with the engine besides the fuel pump. If the pressure reads zero, check all of the electrical components that power the pump, including the fuel pump fuse, relay and inertia switch. If the electrical components are good, the fuel pump is bad.