ROUGH IDLE OR SEAT SHAKE (REVISED CALIBRATION)

SUBJECT: ROUGH IDLE OR SEAT SHAKE (REVISED CALIBRATION)

VEHICLES AFFECTED: 1992 CHEVROLET CORSICA, BERETTA "L" CAR WITH 2.2L ENGINE (VIN 4) AND AUTOMATIC TRANSMISSION

Condition:

--------- Some owners of 1992 Corsica and Berettas may comment of a rough idle or seat shake inside the car at idle.

Cause:

----- Engine idle speed causing a harmonic resonance in the vehicle.

Correction:

---------- A revised calibration has been released to raise the engine idle speed in automatic transmission cars from 600 to 800 rpm.

Install the appropriate calibration from the following chart with a T100 (GM-CAMS) or a Tech 1 according to the User's Manual instructions provided with the cartridge (TK06032A).

Car Trans Emission Part Broadcast Scanner Body Type Type Number Code I.D. ---- ----- -------- ------ --------- ------- L Auto Federal 16176091 BATU 6091

For vehicles repaired under warranty claim:

Labour Time: .3 Hours

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.