If you suspect insufficient fuel delivery, first check the battery to ensure it is fully charged, then inspect the fuel filter for obstructions, which is attached to the bottom of the fuel pump/fuel level sending unit module. Next, examine the fuel line, hoses, and quick-connect fittings to verify that there is no leak in a line. Verify that the fuel pump actually runs by removing the fuel filler cap and having an assistant turn the ignition switch to ON while you listen for the sound of the fuel pump operating; a brief whirring noise indicates the pump is pressurizing the system. If there is no sound, check the fuel pump electrical circuit. If the pump runs but a fuel system problem persists, proceed to check the fuel pump pressure. Before doing so, ensure you have a fuel pressure gauge capable of measuring up to 70 psi and an adapter for the Schrader valve-type test port on the
Fuel Rail. Relieve the fuel system pressure, then connect the fuel pressure gauge and hose to the test port after unscrewing the test port cap. Start the engine and let it idle; the fuel pressure should be within the operating range. If the pressure is higher than specified, replace the fuel pump module. If it is lower, check the fuel line, hoses, connectors, and injectors for leaks, and inspect the fuel strainer for restrictions. If all components are okay, the fuel pressure regulator or fuel pump may be defective, necessitating a replacement of the fuel pump module. After testing, relieve the fuel pressure, remove the gauge, and reinstall the cap on the test port. If the pump does not turn on, check the fuel pump fuse and relay located in the Power Distribution Center; if they are good and the pump still does not operate, check the fuel pump circuit.