Relieve the fuel pressure and disconnect the cable from the negative terminal of the battery. Remove the air filter housing and, using the special spring lock coupling tool, disconnect the fuel line(s) from the fuel rail by pressing down to release the safety clamp, installing the correct diameter tool, and pushing away from the fuel rail to release the internal locking mechanism. Disconnect the injector connectors and remove the vacuum hose from the
Fuel Pressure Regulator. Remove the EGR pipe from the intake manifold and the exhaust manifold, disconnecting any other interfering EGR system components. Disconnect the PCV hose from the engine, ensuring all interfering hoses are disconnected, and for 2005 and later models with a 5.4L engine, also remove the FRPT sensor. For 2005 and later models with a 6.8L engine, disconnect the wiring from the throttle body connectors and the FRPT sensor, then disconnect the wiring harness retainer and move it aside for access. Remove the fuel rail mounting bolts and carefully remove the fuel rail with the fuel injectors attached as an assembly, using a rocking, side-to-side motion while lifting to remove the injectors from the fuel rail. Inspect the injector O-rings for signs of deterioration and replace as required, noting that it's advisable to replace all O-rings while the fuel rail is off. Inspect the injector plastic "hat" and washer for signs of deterioration and replace as necessary, checking for a missing hat in the intake manifold. Ensure that the injector caps are clean and free of contamination, then place the fuel rail over each of the injectors, seating them well in the fuel rail assembly. It may be easier to seal the injectors in the fuel rail and then seal the entire assembly in the lower intake manifold. Secure the fuel rail assembly with the retaining bolts and tighten them to the specified torque, with the remainder of the installation being the reverse of removal.