BASE IDLE RPM ADJUSTMENT REVISED PROCEDURE AND SPEC.

MODELS AFFECTED: 1987-88 SKYHAWKS

The "minimum idle speed adjustment" in the Service Manual, Section 6E2-C2 specifies an idle setting that is too tightly held. "Minimum idle RPM" will depend upon miles on the engine, altitude, accessory load, etc.; thus implying a broader acceptable range than currently specified. This factory set air gap clearance (throttle blade-to-bore) should not require any resetting UNLESS the TBI's throttle body is replaced. If the throttle body is replaced, then the following wider setting band should be used with the setting procedure specified in Section 6E2-C2.

HOT IDLE

L-4 Engine 1987 1988 ---------- ---- ---- VIN Code 1 450-650 450-650 VIN Code K 450-600 450-600

NOTICE: Once the idle air control (IAC) motor is reconnected, a higher ECM controlled idle RPM overrides the base "Minimum Idle Speed" via the IAC controlled air path into the intake manifold.

The IAC's proper count position should be checked, refer to Chart C-2C, and if necessary, reset the IAC valve position by driving the vehicle at its "reset speed" (45 mph) as stated in Section 6E2-2C.

Use applicable labor time and operation number.

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.