For 1990-2009 cars

# ENGINE DETONATION/CHUGGLE MAY NEED SERVICE PROM

#### VEHICLES AFFECTED: 1983-86 'A AND X' CARS WITH AUTOMATIC 3 SPEED TRANSMISSIONS

Some 1983/84/85 and 86 'A' and 'X' cars equipped with 2.8L, V 6 carbureted engines may exhibit engine detonation or chuggle. If normal service procedures in the Service Manual (Section 6E1, Section B) do not correct the condition, new serivce PROMS with revised calibrations are now available.

The model applications are:

#### MODEL EMISSIONS SERVICE YEAR MODELS TRANSMISSION CALIBRATION PROM ---- ------ ------------ ----------- ---- 83 1,2 AAOO;1,2,3,4 XAOO 3 Spd. Auto. Federal 1228323 84 1,2,4 AAOO;1,2,3,4 XAOO 3 Spd. Auto Federal 1228325 85 1,2,3,4AAOO;1,4 XAOO 3 Spd. Auto Federal 1228326 86 1,2,3,4AAOO 3 Spd. Auto. Federal 1228326

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.