Idle Speed: Adjustments

NOTE: This adjustment should be performed only when the throttle body assembly has been replaced. Engine should be at normal operating temperature before making adjustment. The screw is covered with a plug to discourage unauthorized adjustments.

Idle Air Flow:

MINIMUM AIR RATE ADJUSTMENT
1. Before adjusting the minimum air rate or idle speed to specifications, make sure the Idle Air Control (IAC) valve pintle is fully extended or bottomed out in its seat.

Concealment Plug Removal:

2. Remove air cleaner, then remove idle screw concealment plug.
3. Warm engine to normal operating temperature, and connect a tachometer.

ALDL Connector:

4. With the IAC valve connected, ground the diagnostic "test" terminal in the Assembly Line Diagnostic Link (ALDL) connector. (Connect jumper between terminals "A" and "B".)
5. Turn ignition "ON", but do not start engine. Wait at least 30 seconds to allow the IAC pintle to fully seat, closing the air passage.
6. With ignition "ON", engine stopped and diagnostic lead grounded, disconnect the IAC valve electrical connector.
7. Remove ground from the ALDL connector and start the engine. Allow the engine speed to stabilize.
8. Adjust the idle stop screw to 675-725 rpm.
9. Turn ignition "OFF" and reconnect the IAC connector.
10. Start engine and run at 2000 RPM for ten seconds to reset the idle air control valve pintle position. Turn ignition off.
11. Cover idle stop screw with silicone or similar sealant.
12. Remove test instruments and reinstall air cleaner.