CHUGGLE AT LOW SPEEDS & D.I.C. INACCURATE MILEAGE-NEW MEM-CAL

Subject: CHUGGLE AT LOW SPEED (28-37 MPH) NEW MEM-CAL

Models Affected: 1989-90 GRAND AM MODELS W/2.3L (VIN D) AND 3T40

If concerns about chuggle between speeds of 28 - 37 mph are received and thorough diagnosis of the engine control system does not resolve the concern, you may need to install a revised Mem-Cal.

PARTS INFORMATION:

Model Transaxle Emissions Number I.D. Code ----- --------- --------- -------- ---- ---- 1989 Auto Federal 16156388 6353 AWNB 1989 Auto California 16156393 6363 AWNC

1990 Auto Federal 16156310 5993 AWLU 1990 Auto California 16156315 6003 AWLW

These Mem-Cals raise the TCC engagement speed to 37 mph and reduces the throttle position, crowd release of TCC. However, vehicle fuel economy may be affected. Be sure to advise the owner of this.

NOTICE: This Mem-Cal is intended to be used on an as needed basis. The part number will be in GMSPO but as a field fix only. This will not be published in the GMSPO catalog.

Parts are currently available from GMSPO.

WARRANTY INFORMATION

Labor Operation Number: T0500 Labor Time: 0.4 hour Trouble Code: 92

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.