STALL/SURGE AFTER COLD START DIAGNOSIS P/N FOR NEW PROM

VEHICLES AFFECTED: 1986 'A' CARS WITH 2.8L (VIN CODE W) MPFI ENGINE AND 4 SPEED AUTOMATIC TRANSMISSION

Some 1986 'A' cars with 2.8L MPFI engines and 4 speed automatic transmissions may experience a stall after cold start or engine surge after cold start at 10 degrees C (50 degrees F) to 21 degrees C (70 degrees F) ambient temperatures.

To correct this condition inspect for the following and correct as necessary:

1. Loose or leaking air duct between mass airflow (MAF) sensor and throttle body.

2. Low base idle air rate.

3. Openings in the EGR transfer tube.

If the condition persists, replace the PROM with one of the following service PROMs. AIR SERVICE SALES MODELS AXLE CONDITIONING PROM ----- ------ ---- ------------ ---- Federal 1AW19,27 3.06/3.33 Yes 1228070

Federal 1AW19,27 3.06/3.33 No 1228071 2AF/AG19,27 3.33 No 1228071

Federal 1AW35 3.06/3.33 Yes 1228085 2AAOO 3.33 Yes 1228085

Federal 1AW35 3.06/3.33 No 1228101 2AF/AG35 3.33 No 1228101

California 1AW19,27 3.06/3.33 Yes 1228072

California 1AW19,27 3.06/3.33 No 1228078 2AF/AG19,27 3.06 No 1228078

California 1AW35 3.06/3.333 Yes 1228102 2AAOO 3.33 Yes 1228102

California 1AW35 3.06/3.33 No 1228103 2AF,AG35 3.33 No 1228103

NOTICE: The above PROMs are for 'A' car, 2.8L port fuel injected engines with 4 speed automatic transmissions.

Use applicable labour time and operation numbers.

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.