Important: The intake manifold, throttle body, fuel injection rail, and injectors may be removed as an assembly. If not servicing the individual components, remove the manifold as a complete assembly.

1. Drain the cooling system. Refer to Cooling System Draining and Filling in Engine Cooling.
2. Relieve the fuel system pressure. Refer to Fuel Pressure Relief in Engine Controls - 5.7L.
3. If replacing the intake manifold, perform the following:

•	Remove the throttle body. Refer to Throttle Body Assembly Replacement in Engine Controls - 5.7L.

•	Remove the fuel injectors. Refer to Fuel Injector Replacement in Engine Controls - 5.7L.




4. Disconnect the fuel feed hose (2). Refer to Fuel Hose/Pipes Replacement - Engine Compartment in Engine Controls - 5.7L.



5. Disconnect the evaporative emission (EVAP) canister purge tube from the intake manifold.
6. Disconnect the EVAP canister purge tube from the EVAP canister purge solenoid valve.
7. Remove the EVAP canister purge tube.



8. Disconnect the EVAP canister purge tube (4) from the EVAP canister purge solenoid valve.
9. Disconnect the EVAP canister purge tube from the fuel feed pipe.
10. Disconnect the EVAP canister purge tube from the rear of the right cylinder head (1).
11. Remove the EVAP canister purge tube from under the fuel rail and remove the tube from the vehicle.



12. Disconnect the throttle position (TP) sensor electrical connector.
13. Remove the coolant air bleed hose. Refer to Engine Coolant Air Bleed Hose Replacement in Engine Cooling.



14. Disconnect the throttle body outlet hose (1) from the throttle body.
15. Position the throttle body outlet hose aside.



16. Disconnect all the fuel injector electrical connectors (1).
17. Disconnect the EVAP canister purge solenoid valve electrical connector (2).
18. Disconnect the electronic throttle control (ETC) electrical connector (3).



19. Remove the EVAP canister purge solenoid valve from the bracket.
20. Disconnect the harness clips from the fuel rails.
21. Reposition the intake manifold branches of the wiring harness.



22. Disconnect the power brake booster vacuum hose at the booster.



23. Remove the knock sensor wire harness (1) clip from the fuel rail stop bracket (2).



24. Remove the TP sensor harness clip from the positive crankcase ventilation (PCV) tube.
25. Remove the PCV tube from the right rocker arm cover and the throttle body.



26. Remove the PCV hose from the valley cover and intake manifold.



27. Remove the intake manifold bolts (1) and fuel rail stop bracket (2).
28. Position the intake manifold forward.
29. Disconnect the manifold absolute pressure (MAP) sensor vacuum hose.
30. Disconnect the MAP sensor electrical connector.



31. Remove the intake manifold.



32. Remove and discard the intake manifold gaskets (1).
33. Clean and inspect the intake manifold. Refer to Intake Manifold Cleaning and Inspection .

Important: DO NOT reuse the intake manifold gaskets. Install NEW intake manifold gaskets.

1. Install NEW intake manifold gaskets (1) to the intake manifold.



2. Install intake manifold.
3. Position the intake manifold forward.
4. Connect the MAP sensor vacuum hose.
5. Connect the MAP sensor electrical connector.
6. Position the intake manifold into place.



7. Apply threadlock GM P/N 12345382 (Canadian P/N 10953489), or equivalent to the threads of the intake manifold bolts (1).

Caution: Refer to Fuel Rail Stop Bracket Installation Caution in the Preface section.

8. Install the fuel rail stop bracket (2).
9. Install the intake manifold bolts (1).

Notice: Refer to Fastener Notice in the Preface section.




10. Tighten the intake manifold bolts.

Tighten

1. Tighten the intake manifold bolts a first pass in sequence to 5 N·m (44 lb in).
2. Tighten the intake manifold bolts a second pass in sequence to 10 N·m (89 lb in).



11. Install the PCV hose to the valley cover and intake manifold.



12. Install the PCV tube to the right rocker arm cover and the throttle body.
13. Install the TP sensor harness clip to the PCV tube.



14. Install the knock sensor wire harness (1) clip to the fuel rail stop bracket (2).



15. Connect the power brake booster vacuum hose to the booster.



16. Connect the harness clips to the fuel rails.
17. Install the EVAP canister purge solenoid valve to the bracket.



18. Connect the ETC electrical connector (3).
19. Connect the EVAP canister purge solenoid valve electrical connector (2).
20. Connect the fuel injector electrical connectors (1).



21. Connect the throttle body outlet hose (1) to the throttle body.



22. Install the coolant air bleed hose. Refer to Engine Coolant Air Bleed Hose Replacement in Engine Cooling.
23. Connect the TP sensor electrical connector.



24. Install the EVAP canister purge tube under the fuel rail.
25. Connect the EVAP canister purge tube at the rear of the right cylinder head (1).
26. Connect the EVAP canister purge tube to the fuel feed pipe.
27. Connect the EVAP canister purge tube (4) to the EVAP canister purge solenoid valve.



28. If previously removed, install the fuel injectors. Refer to Fuel Injector Replacement in Engine Controls - 5.7L.
29. Connect the fuel feed hose. Refer to Fuel Hose/Pipes Replacement - Engine Compartment in Engine Controls - 5.7L.
30. If previously removed, install the throttle body. Refer to Throttle Body Assembly Replacement in Engine Controls - 5.7L.
31. Fill the cooling system. Refer to Cooling System Draining and Filling in Engine Cooling.