GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Isuzu 🢒 2009 🢒 Ascender - 4WD 🢒 Engine 🢒 Engine Mechanical - 4.2L 🢒 Intake Manifold Replacement

Removal Procedure
  1. Disconnect the negative battery cable. Refer to Battery Negative Cable Disconnection and Connection.
  2. Relieve the fuel pressure. Refer to Fuel Pressure Relief.
  3. Remove the throttle body. Refer to Throttle Body Assembly Replacement.

    4. Object Number: 1284769 Size: SH
  4. Remove the powertrain control module (PCM) retaining bolts (3) and nuts (6).
  5. Remove the ECM. Refer to Engine Control Module Replacement.

    6. Caution: Refer to Fuel and Evaporative Emission Hose/Pipe Connection Cleaning Caution in the Preface section.


    Object Number: 730718 Size: SH
  6. Disconnect the fuel feed pipe (1) from the fuel rail. Refer to Metal Collar Quick Connect Fitting Service.
  7. Disconnect the integral clip (3) from the wire harness bracket.

    8. Object Number: 1348786 Size: SH
  8. Remove the engine wire harness bracket bolt.
  9. Remove the electrical harness and vacuum lines from the intake manifold.

    10. Object Number: 732831 Size: SH
  10. Disconnect the manifold absolute pressure (MAP) sensor electrical connector.

    11. Object Number: 637635 Size: SH
  11. Disconnect the crankcase ventilation hose from the intake manifold.

    12. Object Number: 748028 Size: SH
  12. Disconnect the vacuum brake booster hose at the intake manifold.
  13. Remove the generator. Refer to Generator Replacement.

    14. Object Number: 637631 Size: SH

    Note: The intake manifold bolts are captured within the intake manifold. Do not attempt to remove the bolts from the intake manifold.

  14. Loosen the intake manifold bolts.
  15. Remove the intake manifold.

Installation Procedure
  1. Install a new intake manifold gasket to the intake manifold.

    2. Caution: Refer to Fastener Caution in the Preface section.


    Object Number: 637631 Size: SH
  2. Install the intake manifold onto the engine and secure the manifold with the bolts.

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

  3. Install the generator. Refer to Generator Replacement.

    4. Object Number: 748028 Size: SH
  4. Install the vacuum brake booster hose to the intake manifold.

    5. Object Number: 637635 Size: SH
  5. Lubricate the inner diameter of the crankcase ventilation hose. Refer to Adhesives, Fluids, Lubricants, and Sealers for the correct part number.
  6. Install the crankcase ventilation hose.

    7. Object Number: 732831 Size: SH
  7. Connect the MAP sensor electrical connector.
  8. Install the electrical harness and vacuum lines to the intake manifold.

    9. Object Number: 1348786 Size: SH
  9. Install the engine electrical harness bracket bolt.

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


    Object Number: 730718 Size: SH
  10. Connect the integral clip (3) to the wire harness bracket.
  11. Connect the fuel feed pipe (1) to the fuel rail. Refer to Metal Collar Quick Connect Fitting Service.

    12. Object Number: 1284769 Size: SH
  12. Install the PCM mounting studs (5) to the intake manifold.

    13. Tighten
    Tighten the studs to 6 N·m (53 lb in).

  13. Install the PCM (1) onto the studs (5).
  14. Install the PCM retaining bolts (3).

    15. Tighten
    Tighten the bolts to 8 N·m (71 lb in).

  15. Install the PCM retaining nuts (6).

    16. Tighten
    Tighten the nuts to 8 N·m (71 lb in).

  16. Install the PCM harness connectors (2) to the PCM body.
  17. Tighten the PCM harness connector retaining bolts (4).

    18. Tighten
    Tighten the bolts to 8 N·m (71 lb in).

  18. Install the throttle body. Refer to Throttle Body Assembly Replacement.
  19. Connect the negative battery cable. Refer to Battery Negative Cable Disconnection and Connection.
  20. Inspect for leaks using the following procedure:
    21. 20.1. Turn ON the ignition, with the engine OFF for 2 seconds.
    20.2. Turn OFF the ignition for 10 seconds.
    20.3. Turn ON the ignition, with the engine OFF.
    20.4. Inspect for fuel leaks.