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

1. Disconnect the mass airflow (MAF) sensor electrical connector (4).
2. Disengage the cover clips (2).
3. Remove the air cleaner cover (1).



4. Loosen the air intake duct clamp at the throttle body.
5. Remove the air intake duct and air cleaner element.
6. Relieve the fuel system pressure. Refer to Fuel Pressure Relief in Engine Controls - 8.1L.



7. Disconnect the exhaust gas recirculation (EGR) valve electrical connector (1).



8. Remove the EGR pipe bolts from the EGR bracket.



9. Disconnect the manifold absolute pressure (MAP) sensor electrical connector.



10. Remove the connector position assurance (CPA) retainer from the following electrical connectors:

•	Fuel injector harness (2)

•	Ignition coil harness (3)

11. Disconnect the following electrical connectors:

•	Air conditioning (A/C) compressor high pressure recirculate switch (1)

•	Fuel injector harness (2)

•	Ignition coil harness (3)

•	A/C compressor high pressure cutoff switch (4)

•	A/C compressor clutch switch (5)

12. Remove the A/C compressor and condenser hose. Refer to Compressor Hose Assembly Replacement in Heating, Ventilation, and Air Conditioning.



13. Disconnect the following electrical connectors:

•	Engine coolant temperature (ECT) sensor (1)

•	Ignition coil harness (2)




14. Disconnect the following electrical connectors:

•	Throttle position (TP) sensor (2)

•	Electronic throttle control (ETC) (3)

•	evaporative emission (EVAP) purge solenoid (4)

15. Remove the wiring harness bolts.
16. Reposition the engine wiring harness.



17. If equipped with regular production option (RPO) C5B, disconnect the EVAP canister tube from the purge solenoid.
18. Disconnect the EVAP canister tube from the canister.
19. Remove the EVAP canister tube.



20. If equipped without RPO C5B, disconnect the EVAP canister tube from the purge solenoid.



21. If equipped without RPO C5B, remove the EVAP canister tube clip from the fuel rail.
22. Disconnect the EVAP canister tube from the canister.
23. Disconnect the fuel line quick connect fittings. Refer to Metal Collar Quick Connect Fitting Service and/or Plastic Collar Quick Connect Fitting Service in Engine Controls - 8.1L.



24. Remove the intake manifold bolts.

Important: Do not attempt to loosen the manifold by prying under the gasket surface with any tool.

25. Remove the intake manifold.




Important: The intake manifold gaskets are not reusable.

26. Remove and discard the intake manifold side gaskets.



27. Remove and discard the lower intake manifold end seals.




Important: The splash shield is secured using a snap-in fit. Do not distort the splash shield. The splash shield is reusable.

28. Remove the intake manifold oil splash shield.



29. If replacing the intake manifold, remove the EVAP purge solenoid bolt and purge solenoid.



30. If replacing the intake manifold, remove the MAP sensor bolt and sensor.
31. Inspect the MAP sensor seal for damage.



32. If replacing the intake manifold, remove the EGR bracket nuts, EGR bracket, and gasket.
33. Discard the EGR gasket.



34. If replacing the intake manifold, remove the throttle body nuts, throttle body, and gasket.
35. Discard the gasket.



36. If replacing the intake manifold, remove the fuel pressure regulator vacuum hose.



37. If replacing the intake manifold, remove the fuel rail studs and fuel rail.

Important: Lubricate the injector O-ring seals with clean engine oil.

1. If replacing the intake manifold, install the fuel rail.

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.

2. Install the fuel rail studs.

Tighten
Tighten the fuel rail studs to 12 N·m (106 lb in).




3. If replacing the intake manifold, install the fuel pressure regulator vacuum hose.



4. If replacing the intake manifold, install a NEW throttle body gasket.
5. Install the throttle body, and nuts.

Tighten
Tighten the throttle body nuts to 10 N·m (89 lb in).




6. If replacing the intake manifold, install a NEW EGR bracket gasket.
7. install the EGR bracket, and nuts.

Tighten
Tighten the EGR bracket nuts to 30 N·m (22 lb ft).





Important: Lubricate the port of the MAP sensor with clean engine oil. Avoid dipping the sensor port directly into the lubricant or using a solid type of lubricant, as they may block the vacuum port signal.

8. If replacing the intake manifold, install the MAP sensor and bolt.

Tighten
Tighten the MAP sensor bolt to 12 N·m (106 lb in).





Important: Apply a very light film of clean engine oil to the purge solenoid seal.

9. If replacing the intake manifold, install the EVAP purge solenoid.
10. Apply sealant GM U.S. P/N 12345493, Canada P/N 10953488, or equivalent to the threads of the purge solenoid bolt.
11. Install the purge solenoid bolt.

Tighten
Tighten the purge solenoid bolt to 10 N·m (89 lb in).




12. Install the intake manifold oil splash shield.



13. Ensure the oil splash shield (2) snap fits between the cylinder heads (1).



14. Install NEW intake manifold end seals.



15. Install NEW intake manifold side gaskets.



16. Ensure the intake manifold gasket tabs align with the hole in the head gasket.
17. Ensure the intake manifold gasket tabs align with the slot in the intake manifold end seals.



18. Install the intake manifold.



19. Apply threadlock GM U.S. P/N 12345382, Canada P/N 10953489, or equivalent to a minimum of eight threads of the intake manifold bolts.

Important: 

•	The entire intake manifold tightening sequence must be followed exactly, or an oil leak resulting in engine damage may occur. Ensure the intake manifold is tightened without allowing the intake manifold to shift.

•	The entire intake manifold tightening sequence must be promptly completed due to anaerobic thread adhesive. The final pass of the tightening sequence must be completed before the adhesive starts to cure, or false torque readings and ineffective thread locking may result.

20. Install the intake manifold bolts.
21. Tighten the intake manifold bolts in sequence, using four passes.

Tighten

1. Snug the intake manifold bolts in sequence to 5 N·m (44 lb in) on the first pass.
2. Snug the intake manifold bolts in sequence to 5 N·m (44 lb in) on the second pass. Inspect the intake manifold joints for signs of intake manifold shifting. Correct as required.
3. Tighten the intake manifold bolts in sequence to 10 N·m (89 lb in) on the third pass.
4. Tighten the intake manifold bolts in sequence to 12 N·m (106 lb in) on the final pass.
22. Connect the fuel line quick connect fittings.



23. If equipped without RPO C5B, install the EVAP tube.
24. Connect the EVAP canister tube to the canister.
25. Connect the EVAP canister tube clip to the fuel rail.



26. If equipped without RPO C5B, connect the EVAP canister tube to the purge solenoid.



27. If equipped with RPO C5B, install the EVAP tube.
28. Connect the EVAP canister tube to the purge solenoid.
29. Connect the canister tube to the canister.



30. Position the wiring harness.
31. Install the wiring harness bolts.

Tighten
Tighten the engine wiring harness bolts to 5 N·m (44 lb in).

32. Connect the following electrical connectors:

•	TP sensor (2)

•

ETC (3)

•	EVAP purge solenoid (4)




33. Connect the following electrical connectors:

•	ECT sensor (1)

•	Ignition coil harness (2)

34. Install the A/C compressor and condenser hose. Refer to Compressor Hose Assembly Replacement in Heating, Ventilation, and Air Conditioning.



35. Connect the following electrical connectors:

•	A/C compressor high pressure recirculate switch (1)

•	Fuel injector harness (2)

•	Ignition coil harness (3)

•	A/C compressor high pressure cutoff switch (4)

•	A/C compressor clutch switch (5)

36. Install the CPA retainers to the following electrical connectors:

•	Fuel injector harness (2)

•	Ignition coil harness (3)




37. Connect the MAP sensor electrical connector.



38. Install the EGR pipe bolts to the EGR bracket.

Tighten
Tighten the EGR pipe bolts to 30 N·m (22 lb ft).




39. Connect the EGR valve electrical connector (1).



40. Install the air intake duct and air cleaner element.
41. Tighten the air intake clamp at the throttle body.

Tighten
Tighten the air intake duct clamp to 3 N·m (26 lb in).




42. Install the air cleaner cover (1).
43. Engage the cover clips (2).
44. Connect the MAF sensor electrical connector (4).