Removal Procedure

Important:  You do not have to remove the upper intake manifold in order to remove the lower intake manifold.

1. Disconnect the negative battery cable. Refer to BATTERY NEGATIVE CABLE DISCONNECT/CONNECT PRO in Battery.
2. Disconnect the breather tube at the air cleaner outlet duct.
   Fig 1: Disconnecting Breather Tube From Air Cleaner Outlet Duct

   Courtesy of GENERAL MOTORS CORP.
3. Remove the air cleaner outlet duct.
   Fig 2: Removing Air Cleaner Outlet Duct

   Courtesy of GENERAL MOTORS CORP.
4. Disconnect the accelerator cable from the throttle body.
   Fig 3: Disconnecting Accelerator Cable from Throttle Body

   Courtesy of GENERAL MOTORS CORP.
5. Remove the accelerator cable from the accelerator control cable bracket.
6. Disconnect the cruise control cable, if equipped, from the throttle shaft and the accelerator cable bracket. Refer to CRUISE CONTROL CABLE REPLACEMENT (4.3L) in Cruise Control.
   Fig 4: View of Cruise Control Cable

   Courtesy of GENERAL MOTORS CORP.
7. Disconnect the vacuum hose from the intake manifold, if equipped with A/C.
8. Disconnect the power brake booster vacuum hose
   Fig 5: Disconnecting Power Brake Booster Vacuum Hose

   Courtesy of GENERAL MOTORS CORP.
9. Drain the cooling system. Refer to DRAINING AND FILLING COOLING SYSTEM in Engine Cooling.
10. Remove the radiator inlet hose at the water outlet. Refer to RADIATOR HOSE REPLACEMENT - INLET (4.3L) in Engine Cooling.
11. Remove the heater hose from the intake manifold. Refer to HEATER HOSE REPLACEMENT - INLET (4.3L) and HEATER HOSE REPLACEMENT - OUTLET (4.3L) in Heating, Ventilation and Air Conditioning.
12. Remove the water pump inlet hose from the intake manifold.
    Fig 6: Removing Radiator Inlet Hose

    Courtesy of GENERAL MOTORS CORP.
13. Disconnect the following electrical connectors:
    • The fuel meter body assembly (1)
    • The EVAP canister purge solenoid valve (2)
    • The manifold air pressure (MAP) sensor (3)
      Fig 7: Disconnecting Electrical Connectors

      Courtesy of GENERAL MOTORS CORP.
14. Disconnect the following electrical connectors:
    • The ignition coil (2)
    • The ignition control module (ICM) (1)
    • The generator (4)
      Fig 8: Disconnecting Electrical Connectors

      Courtesy of GENERAL MOTORS CORP.
15. Disconnect the following electrical connectors:
    • The idle air control (IAC) motor (3)
    • The throttle position (TP) sensor (2)
    • The A/C compressor cutoff switch, if equipped (5)
    • The A/C clutch switch, if equipped (1)
    • The engine coolant temperature (ECT) sensor (4)
16. Remove the engine wiring harness clips from the brackets.
17. Move the engine wiring harness aside.
    Fig 9: Disconnecting Electrical Connectors

    Courtesy of GENERAL MOTORS CORP.
18. Remove the accelerator cable bracket from the throttle body and the intake manifold.
    Fig 10: View of Accelerator Cable Bracket

    Courtesy of GENERAL MOTORS CORP.
19. Remove the accelerator and the cruise control cable bracket from the throttle bracket.

    Leave the accelerator and cruise control cables on the bracket.

    Fig 11: Removing Accelerator and Cruise Control Cable Bracket

    Courtesy of GENERAL MOTORS CORP.
20. Disconnect the PCV hose assembly from the intake manifold and the valve rocker arm cover.
21. Remove the EVAP canister purge solenoid valve. Refer to EVAP CANISTER in Removal and Installation in Engine Performance.
    Fig 12: View of PCV Hose

    Courtesy of GENERAL MOTORS CORP.
22. Remove the distributor. Refer to DISTRIBUTOR in Removal and Installation in Engine Performance.
23. Disconnect the fuel supply and return pipes at the rear of the intake manifold.

    Important:  Do not discharge the refrigerant.

24. Perform the following in order to remove the left front bolt for the intake manifold:
    1. 24.1. Remove the drive belt. Refer to Drive Belt Replacement  .
    2. 24.2. Loosen the nut for the power steering pump rear bracket at the side of the engine.
    3. 24.3. Remove the nut for the power steering pump rear bracket at the front of the engine.
    4. 24.4. Remove the bolts and the nut for the power steering pump mounting bracket.
    5. 24.5. Leave the A/C compressor, if equipped, and the power steering pump on the power steering pump mounting bracket.
    6. 24.6. Slide the power steering pump bracket forward to access the bolt at the front of the intake manifold.
       Fig 13: Identifying Intake Manifold Bolts

       Courtesy of GENERAL MOTORS CORP.
25. Remove the engine coolant temperature (ECT) sensor wire connector (if equipped) from the engine wiring harness bracket.
26. Remove the lower intake manifold bolts.

    Important:  The intake manifold may be removed as an assembly. Do not remove the specific intake manifold components unless component service is required.

    Do not allow dirt or debris to enter the fuel system. Ensure that the ends of the fuel system are properly sealed.

    Do not disassemble the Central Sequential Fuel Injection (SFI) unit, unless service is required.

27. Remove the intake manifold assembly.
28. Remove and discard the lower intake manifold gaskets.
    Fig 14: Removing Lower Intake Manifold Gaskets

    Courtesy of GENERAL MOTORS CORP.

    Important:  Do not immerse the assembled intake manifold in cleaning solvent.

29. Clean the lower intake manifold in cleaning solvent.
30. Dry the lower intake manifold with compressed air.
    Fig 15: Cleaning Lower Intake Manifold

    Courtesy of GENERAL MOTORS CORP.
31. Inspect the lower intake manifold for the following:
    • Damage to the gasket sealing surfaces (1), (2) and (3)
    • Restricted cooling system passages (5)
    • Cracks or damage
    • Damage to the threaded bolt holes
32. If the intake manifold requires replacement refer to Intake Manifold Disassemble (LU3)  and Intake Manifold Assemble (LU3)  .
    Fig 16: Inspecting Lower Intake Manifold

    Courtesy of GENERAL MOTORS CORP.