GM Service Manual Online
For 1990-2009 cars only

MININUM IDLE SPEED ADJ. SHOP MANUAL CORRECTION

VEHICLES AFFECTED: All 1986 With 3.0L or 3.8L Fuel Injected Engines

The minimum idle speed adjustment procedures for the 3.0L and 3.8L engines in some Chassis Service Manuals is incorrect. Following is the correct procedure to adjust the minimum idle speed.

1. With IAC motor connected, ground diagnostic lead.

2. Turn on ignition, do not start engine. Wait at least 30 seconds.

3. With ignition 'on', disconnect IAC electrical connector.

4. Remove ground from diagnostic lead and start engine.

5. Adjust idle stop screw to 500 plus/minus 50 rpm in drive.

6. Turn ignition 'off' and reconnect connector at IAC connector.

7. Adjust TPS to: - .40 plus/minus .05 volts on 3.8L - .50 plus/minus .05 volts on 3.0L

8. Recheck setting.

9. Start engine and inspect for proper idle operation.

General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.