GM Service Manual Online
For 1990-2009 cars only

SPARK PLUG FOULING CORRECTION TO REDUCE PLUG FOUL

THE FOLLOWING ACTIONS WILL REDUCE THE POSSIBILITY OF SPARK PLUG FUEL FOULING. IT IS VERY IMPORTANT THAT CHOKE SETTING AND OPERATION, SECONDARY VACUUM BREAK AND FAST IDLE SPEED, ARE SET TO SPECIFICATIONS. IN ADDITION, PERFORM THE FOLLOWING OPERATIONS: (1) PRIMARY VACUUM BREAK SETTING SHOULD BE: A.24 DEGREES FOR AUTOMATIC TRANSMISSIONS. B.22 DEGREES FOR MANUAL TRANSMISSIONS. (2) WIDE OPEN KICK - CHOKE UNLOADER SHOULD BE CHECKED AND IF LESS THAN 35 DEG. RESET TO 40 DEG. NOTE: WIDE OPEN KICK SETTING SHOULD BE MADE BY ACTUATING THE SYSTEM FROM THE ACCELERATOR PEDAL INSIDE THE CAR TO ASSURE THAT FULL W.O.T. OCCURS. (3) FUEL FOULED SPARK PLUGS SHOULD BE REPLACED WITH R43TS (R43CTS WHEN AVAILABLE). USE APPLICABLE LABOR OPERATION.

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.