IDLE SHAKE CONDITION WITH A/T (NEW CALIBRATION FOR IDLE RPM)

SUBJECT: REVERBERATING NOISE AND OR IDLE SHAKE CONDITION (NEW CALIBRATION)

VEHICLES AFFECTED: 1992 CHEVROLET CAVALIER J-CAR WITH 2.2L (VIN CODE 4) AND A/T ONLY

Condition:

--------- Some owners of 1992 J-cars with 2.2L engine and A/T (Automatic Transmission) may comment of a rough idle. In addition to this, some owners may also comment of either a reverberating noise coming from the engine area or seat shake inside the car at idle.

Cause:

----- This is caused by the engine idle speed exciting a harmonic resonance in the vehicle.

Correction:

---------- A new calibration has been released to raise the engine idle speed in automatic J-cars from 800 to 875 RPM. The J-car calibration has been changed in Production. Install the calibration shown below with a T-100 (GM-CAMS) or a Tech 1 according to User's Manual instructions provided with the cartridge. The Tech 1 cartridge part number is TK06032A, that has been sent to dealers. The calibration was included in the January, 1992 Software Update for the T-100.

Car Trans Emission Part Broadcast Scanner Body Type Type Number Code I.D. -----------------------------------------------------

J Auto Federal 16174821 BALM 4821

For vehicles repaired under warranty use: Labour Time 0.3 HRS.

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.