IDLE SHAKE/DETONATION PROM CALIBRATION REVISION

A NEW PROM HAS RECENTLY BEEN RELEASED WITH REVISED SPARK TIMING CALCULATIONS AND SLIGHTLY INCREASED IDLE SPEEDS. THE CHANGE IN SPARK TIMING WAS MADE TO ELIMINATE ANY DETONATION UNDER MODERATE ACCELERATION AT CRUISING SPEEDS (40-55 MPH). THE INCREASED IDLE SPEED WILL REDUCE VIBRATION OR SHAKE AT IDLE SPEEDS. THE SERVICE PART NUMBER FOR THIS NEW PROM IS 1226169 (BROADCAST CODE 0262-AOS). THIS PROM IS TO ONLY BE USED ON 1982 PHOENIX AND 6000'S WITH THE 2.5L EFI, AUTOMATIC TRANSAXLE, AND FIRST DESIGN (3-BOARD) ECM. THE SECOND DESIGN (2-BOARD) ECM HAS THE SPARK REVISION ALREADY INCORPORATED IN ITS PROM. PROM'S SHOULD BE REPLACED ONLY AS REQUIRED TO CORRECT ABOVE CONDITIONS

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.