An 8-digit identification number is stamped on the left hand fuel rail (fueling even cylinders 2, 4, 6). Refer to this number if servicing or part replacement is required.

Caution: In order to reduce the risk of fire and personal injury that may result from a fuel leak, always install the fuel injector O-rings in the proper position. If the upper and lower O-rings are different colors (black and brown), be sure to install the black O-ring in the upper position and the brown O-ring in the lower position on the fuel injector. The O-rings are the same size but are made of different materials.

Notice: Cap the fittings and plug the holes when servicing the fuel system in order to prevent dirt and other contaminants from entering the open pipes and passages.

1. Relieve fuel system pressure. Refer to Fuel Pressure Relief .
2. Remove the upper intake manifold. Refer to Upper Intake Manifold Replacement in Engine Mechanical - 3.4L.
3. Remove the engine fuel feed pipe from the fuel rail.



4. Remove the engine fuel return pipe from the fuel pressure regulator.
5. Remove the fuel feed pipe and fuel return pipe O-rings and discard.
6. Disconnect the main injector harness electrical connector.
7. Disconnect the main fuel injector electrical harness connector.



8. Pull up the lock release (2) of the fuel injector electrical connectors.



9. Depress the lock tabs (1) and disconnect the fuel injector electrical connectors.



10. Disconnect the engine coolant temperature (ECT) sensor electrical connector.
11. Remove the fuel injector electrical wiring harness from the fuel rail.



12. Remove the fuel rail bolts.
13. Remove the fuel rail assembly.
14. Remove the fuel injector O-ring seal from the spray tip end of each injector.
15. Remove and discard O-rings if damaged.

Notice: 

•	Use care when servicing the fuel system components, especially the fuel injector electrical connectors, the fuel injector tips, and the injector O-rings. Plug the inlet and the outlet ports of the fuel rail in order to prevent contamination.

•	Do not use compressed air to clean the fuel rail assembly as this may damage the fuel rail components.

•	Do not immerse the fuel rail assembly in a solvent bath in order to prevent damage to the fuel rail assembly.

1. Replace any damaged O-ring seals that were removed.
2. Lubricate the O-ring seals with clean engine oil.
3. Install the fuel rail assembly into the intake manifold. Tilt the fuel rail assembly slightly to install the injectors.

Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

4. Install the fuel rail bolts.

Tighten
Tighten the bolts to 10 N·m (89 lb in).

5. Install the fuel injector electrical wiring harness to the fuel rail.



6. Connect the ECT sensor electrical connector.



7. Connect the fuel injector electrical connectors.
8. Push the slide locks (2) into position.
9. Connect the main fuel injector electrical harness connector.



10. Install the new O-rings on the fuel feed and the fuel return pipes.
11. Install the fuel feed pipe to the fuel rail.

Tighten
Tighten the fuel feed pipe nut to 17 N·m (13 lb ft).




12. Install the fuel return pipe to the fuel pressure regulator.

Tighten
Tighten the fuel return pipe nut to 17 N·m (13 lb ft).

13. Install the upper intake manifold. Refer to Upper Intake Manifold Replacement in Engine Mechanical - 3.4L.
14. Connect the negative battery cable. Refer to Battery Negative Cable Disconnection and Connection in Engine Electrical.
15. Inspect for fuel leaks with the following procedure:

15.1.

Turn ON the ignition for 2 seconds.

15.2.

Turn OFF the ignition for 10 seconds.

15.3.

Turn ON the ignition.

15.4.

Inspect for fuel leaks.