See Figures 1, 2, 3 and 4
Observe all applicable safety precautions when working around fuel. Whenever servicing the fuel system, always work in a well ventilated area. Do not allow fuel spray or vapors to come in contact with a spark or open flame. Keep a dry chemical fire extinguisher near the work area. Always keep fuel in a container specifically designed for fuel storage; also, always properly seal fuel containers to avoid the possibility of fire or explosion.
Remove the engine cover.
Remove the air cleaner assembly.
Remove the protective cap from the fuel pressure test port on the fuel rail.
Install fuel pressure gauge C-5069 or equivalent to the test port fitting.
Start the engine and check fuel pressure; at idle, the pressure should be 35-45 psi.
If pressure fails to meet specifications, perform normal diagnostics.
Install all removed components after servicing the fuel system.
Fig. Fig. 1: On 5.2L and 5.9L engines, the fuel pressure test port is located on the driver's side fuel rail. Remove the cap to test fuel pressure
Fig. Fig. 2: Location of the fuel pressure test port on a 3.9L MFI engine
Fig. Fig. 3: Location of the fuel pressure test port on 5.2L and 5.9L MFI engines
Fig. Fig. 4: Use fuel pressure gauge C-5069 or equivalent to test the fuel pressure on an MFI equipped vehicle