ENGINE DETONATION/CHUGGLE MAY NEED SERVICE PROM

MODELS AFFECTED: 1983-85 SKYLARKS AND 1986 CENTURYS WITH LE2 2.8L V-6 ENGINES (VIN CODE X), 3 SPEED AUTOMATIC TRANSMISSIONS, AND FEDERAL EMISSIONS

Some 1983-85 Skylarks and 1986 Centurys equipped with 2.8L V-6 carbureted engines may exhibit engine detonation or chuggle upon TCC apply. If normal service procedures in the Service Manual (Section 6E1, Section B) do not correct the condition, new service PROMS with revised calibrations are now available from GMSPO.

MODEL EMISSIONS SERVICE YEAR MODELS TRANSMISSION CALIBRATION PROM ----- ------ ------------ ----------- ---- 1983 Skylark 3 Speed Auto. Federal 1228323 1984 Skylark 3 Speed Auto. Federal 1228325 1985 Skylark 3 Speed Auto. Federal 1228326 1986 Century 3 Speed Auto. Federal 1228326

Use applicable Labor Time and Labor Operation Number for PROM replacement.

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.