GM Service Manual Online
For 1990-2009 cars only

Removal Procedure


    Object Number: 12804  Size: SH
  1. Remove the negative battery cable.
  2. Remove the air intake duct.
  3. Remove the accelerator cable splash shield from the accelerator cable bracket.
  4. Remove the accelerator, cruise, and transmission control cables.
  5. Remove the vacuum hose harness from the top of the air inlet.
  6. Disconnect the crankcase ventilation valve and the power brake vacuum hoses from the vacuum tubes at upper manifold (position vacuum hoses out of the way).
  7. Remove the electrical connectors at the MAP sensor, TP sensor, and IAC valve.
  8. Remove the bolts/nuts attaching the accelerator cable bracket (position bracket and cables out of the way).
  9. Remove the MAP sensor.
  10. Remove the bolts/studs (1) attaching upper manifold to lower manifold (position fuel injector wiring harness out of the way).
  11. Remove the upper manifold assembly (2) and gasket (3) (discard gasket).
  12. Notice: Use care when cleaning the old gasket from the aluminum surfaces in order to prevent damage to the sealing surfaces.

  13. Clean the gasket mating sufaces.
  14. Inspect the replacement upper manifold for items that are to be transferred to the new manifold.
  15. Disassemble the upper manifold following the component repair procedures.
  16. Assemble the replacement upper manifold with the transferred parts following the component repair procedures.

Installation Procedure

    Notice: The EVAP canister may have released carbon particles which caused this part to fail and may cause damage to other components. Check the EVAP canister for loose carbon before returning the vehicle to service.


    Object Number: 12804  Size: SH
  1. Install the new upper manifold gasket (3).
  2. Install the upper manifold assembly (2) (reposition injector wiring harness).
  3. Install the upper manifold attaching bolts/studs (1).

  4. Object Number: 13314  Size: SH
  5. Tighten the upper manifold bolts/studs to the tightening sequence shown.
  6. Tighten
    Tighten the upper manifold bolts/studs to 30 N·m (22 lb ft). Refer to tightening sequence.

    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.


    Object Number: 12804  Size: SH
  7. Install the MAP sensor.
  8. Install the accelerator cable bracket with attaching bolt/nuts.
  9. Tighten

        • Tighten the accelerator cable bracket nut to 30  N·m (22 lb ft).
        • Tighten the accelerator cable bracket bolts to 25 N·m (18 lb ft).
  10. Install the accelerator, cruise, and transmission control cables.
  11. Install the splash shield to accelerator bracket.
  12. Tighten
    Tighten the accelerator cable splash shield screws to 1.9 N·m(17 lb in).

  13. Install the electrical connectors to MAP sensor, TP sensor, IAC valve, and EGR vacuum solenoid.
  14. Install the vacuum hose harness to top of air inlet.
  15. Connect crankcase ventilation valve and power brake vacuum hoses to vacuum tubes at upper manifold.
  16. Install the air intake duct.
  17. Install the negative battery cable.

Removal Procedure


    Object Number: 12802  Size: SH
  1. Relieve fuel system pressure. Refer to theFuel Pressure Relief Procedure
  2. Remove the negative battery cable.
  3. Remove the upper manifold assembly.
  4. Remove the quick-connect fittings at engine compartment fuel feed and return pipes.
  5. Use compressed air in order to blow out dirt from all quick-connect fittings before removing.
  6. Grasp both ends of one fuel pipe connection and twist 1/4 turn in each direction to loosen any dirt in quick-connect fitting. Repeat for other fitting.
  7. Choose correct tool from J 37088-A tool set for size of fitting.
  8. Insert tool into female connector, then push inward to release male connector.
  9. Repeat for other fitting.
  10. Remove the plug fuel feed and return pipes as required.
  11. Remove the bolts retaining power steering pump brace, and brace.
  12. Remove the engine fuel inlet pipe retainer nuts and retainers.
  13. Remove the fuel inlet pipe and seal.
  14. Remove the transmission fill tube attaching nut.
  15. Remove the lower manifold attaching nuts (3).
  16. Remove the lower manifold (2). Discard gasket (1)
  17. Notice: Use care when cleaning the old gasket from the aluminum surfaces in order to prevent damage to the sealing surfaces.

  18. Whenever it is necessary to remove rust or burrs from the male tube end of the fuel feed/return pipes quick-connect fittings, use emery cloth in a circular motion with the tube end to prevent damage to O-ring sealing surface.
  19. Gasket mating surfaces.
  20. Using a clean shop towel, wipe off male tube end of the fuel feed/return pipes quick-connect fittings. Replace pipes if damaged.
  21. Inspect the lower manifold for items that are to be transferred to the new manifold.
  22. Disassemble the lower manifold and other remaining parts to be transferred following component repair procedures.
  23. Assemble the replacement lower manifold with transferred parts following component repair procedures.

Installation Procedure


    Object Number: 12802  Size: SH
  1. Install the new lower manifold gasket (1).
  2. Position lower manifold (2) on studs.

  3. Object Number: 13309  Size: SH
  4. Install the fuel inlet pipe retaining nut.
  5. Tighten
    Tighten the fuel inlet pipe retaining nut to 30 N·m (22 lb ft).

    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.

  6. Install the fuel pipe support nut.
  7. Tighten
    Tighten the fuel pipe support nut to 10 N·m (89 lb in).

  8. Install the lower manifold attaching nuts (3).
  9. Tighten
    Tighten the lower manifold attaching nuts 30.0 N·m (22 lb ft), using tightening sequence.


    Object Number: 12802  Size: SH
  10. Install the transmission fill tube attaching nut.
  11. Install the new fuel inlet pipe O-ring seal.
  12. Install the fuel inlet pipe nut (Finger tighten only).
  13. Support nut on bottom of lower manifold (Finger tighten only).
  14. Caution: Always apply a few drops of clean engine oil to the male pipe ends before connecting the fuel pipe fittings in order to reduce the risk of fire and personal injury. This will ensure proper reconnection and prevent a possible fuel leak. During normal operation, the O-rings located in the female connector will swell and may prevent proper reconnection if not lubricated.

  15. Install the power steering pump brace with attaching bolts.
  16. Unplug fuel feed and return pipes.
  17. Important: 

       • Apply a few drops of clean engine oil to the male tube ends of the engine fuel feed and return pipes.
       • Push connectors together to cause the retaining tabs/fingers to snap into place.
       • Once installed, pull on both ends of each connection to make sure they are secure.
       • Repeat for other fitting.

  18. Install the fuel feed and return line quick-connect fittings
  19. Install the upper manifold assembly.
  20. Tighten fuel filler cap.
  21. Install the negative battery cable.
  22. Inspect for leaks.
  23. 16.1. Turn the ignition switch ON for 2 seconds.
    16.2. Turn the ignition switch OFF for 10 seconds.
    16.3. Turn the ignition switch ON.
    16.4. Check for fuel leaks.