GM 12587556
Intake Plenum

To replace the upper Intake Manifold, you will remove the ignition off, remove the fuel injector sight shield, disconnect air inlet duct and the Brake Booster Vacuum Hose, purge solenoid valve electrical connector, and purge line from the purge solenoid valve. Then, take out the wiring harness retainer, throttle body electrical connector, and harness clip from the brace/bracket. Get rid of the upper Intake Manifold brace stud , bolt, and brace, pull off the positive crankcase valve (PCV) hose from the right bank camshaft cover, barometric pressure sensor electrical connector, Intake Manifold runner control solenoid electrical connector, and left bank ignition coil harness electrical connector. Use the clip on the harness bracket; take out the pcv; take away the left bank ignition coil wiring harness from the bracket or bolt and bracket from the injector harness as well as take out the upper Intake Manifold bolts, some deflection of the cowl panel may be required to pull out the right rear bolt. Take off the upper Intake Manifold with the Throttle Body, disassemble the Intake Manifold if the replacement is made, and clean and check it. For installation, assemble Intake Manifold if necessary: fit using a new upper Intake Manifold gasket; then fit using the upper Intake Manifold. Tighten the Intake Manifold bolts in a circular order beginning from the center (long bolts) and ending at 23 n.m (17 lb ft). Install the injector harness bracket, and bolt, which should be tightened to 10 n.m (89 lb in), and the left bank ignition coil wiring harness to the bracket, and install the pcv line to the clip on the harness bracket and finally lc to connect the left bank ignition coil harness electrical connector, baro sensor electrical connector, Intake Manifold runner control solenoid electrical connector. Mount the pcv hose onto the right bank cam cover, mount the upper Intake Manifold brace, bolt , and stud , torquing the bolt, and stud to 65 nm (48 lb-ft.) and 10 nm (8 lb-in.) respectively. Make sure the wiring harness connector is engaged properly, checked visually for proper latching. Connect the Throttle Body electrical connector, install wiring harness retainer, connect purge line to purge solenoid valve, connect purge solenoid valve electrical connector, reinstall brake booster vac hose to Intake Manifold, install air inlet ducts, and lastly, install fuel injector sight shield.

If needed, disassemble, clean, and inspect the intake manifold.

Proceed to remove the intake manifold bolts, reposition the intake manifold to access the fuel pipe connector, and take off the fuel feed pipe retainer before disconnecting the fuel feed pipe from the fuel rail.

Disassemble and clean the intake manifold.

Remove the upper intake manifold brace stud, bolt, and brace, followed by disconnecting the positive crankcase ventilation (PCV) hose from the right bank camshaft cover, the barometric pressure sensor electrical connector, and the intake manifold runner control solenoid electrical connector.

The throttle body electrical connector, the fuel feed pipe to the fuel rail, and the purge line to the purge solenoid valve.

Tighten bolt to 65 Nm (48 ft. lbs.) and the other bolt to 10 Nm (89 inch lbs.).

Remove it from the bracket and the intake manifold bolts, ensuring not to remove the upper to lower intake manifold bolts and avoiding damage to the fuel pipe.

Tighten the intake manifold bolts in a circular pattern starting at the center (long bolts) and moving outward to 23 N.m (17 lb ft).

Loosen the plenum duct clamp at the front of the intake manifold and the bolts attaching the intake manifold to the cylinder heads, then remove the intake manifold using an upward lifting motion at the rear.