IDLE SHAKE OR HUNTING NEW IDLE SPEED/MTR MOUNT SHIM

MODELS: 1982-84 CABALLERO MODELS WITH 3.8L (LC3) VIN CODE 9 ENGINES

THIS BULLETIN CANCELS AND SUPERSEDES 83-B-128 (SEPTEMBER, 1983), ALL COPIES OF WHICH SHOULD BE DESTROYED.

MOMENTARY HUNTING AT IDLE

It is possible to encounter a momentary "hunting" at idle on deceleration brake stops. This condition can be minimized by setting the base idle (ISC retracted) to 500 RPM (released spec. was 475). Refer to 1983 Shop Manual, E2ME, Carb. 6C2-5, Idle Speed Adjustment, Items 9-11 for the procedure to make this adjustment.

EXCESSIVE IDLE SHAKE (ALL MODELS LISTED)

A harsh shake may occur at normal idle conditions, A/C on or off. This condition may be caused by grounded engine mounts which can be corrected by installing a shim, P/N 14082881, between the L.H. engine mount and the block and using three (3) longer bolts, P/N 435611. If the drive idle shake is improved, but not to an acceptable level, 6mm of shims should also be installed between the R.H. mount and the block.

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.