3.9L, 5.2L & 5.9L
Disconnect negative battery cable. Loosen fuel filler cap to release tank pressure. Remove protective cap from pressure test port on fuel rail. Using appropriate fuel pressure gauge/hose with gauge removed, place gauge end of hose into approved gasoline container. To release pressure, screw other end of hose onto pressure test port. After pressure is released, remove hose from test port and install protective cap.