Recommended Procedure
WARNING: This page is about a different car, the 2003 Ford Pickup, 2003 Ford F550 Super Duty, 2003 Ford F450 Super Duty, 2003 Ford Excursion, and 2003 Ford Cab & Chassis. However, it is still accessible from the selected car via links, so may be relevant.
Remove the fuel line to the inlet side of the fuel pump. Install Fuel Pump Adapter (310-111) or equivalent between the fuel inlet line and the electric fuel pump. Connect test adapter to vacuum gauge (0-30 in. Hg). Measure restriction at WOT (maximum engine speed out of gear with the brakes set and the wheels blocked). If restriction is greater than 6 in. Hg, there is a restriction between the fuel pump and the fuel tank. If restriction is less than 6 in. Hg, inspect both fuel filters. If filters are okay, inspect the fuel regulator valve. If regulator is okay, install a new fuel pump.