SPARK PLUG FOULING CORRECTION REPLACE PLUGS AND VACUUM BRAKE

SPARK PLUG FOULING CAN OCCUR ON EARLY PRODUCTION VEHICLES SUBJECTED TO REPEATED SHORT TRIPS. THIS COULD THEN RESULT IN A POSSIBLE NO START, ROUGH IDLE OR POOR PERFORMANCE CONDITION. THE FOLLOWING ACTIONS WILL REDUCE THE POSSIBILITY OF SPARK PLUG FOULING AND ARE RECOMMENDED FOR VEHICLES THAT EXHIBIT THIS CONDITION. (1) REPLACE CARBON FOULED SPARK PLUGS WITH THE FOLLOWING: VEHICLE "A" AND "X" ENGINE RPO LE2 SPARK PLUGS R43CTS VEHICLE "F" ENGINE RPO LC1 SPARK PLUGS R43CTS VEHICLE "X"-HI OUTPUT ENGINE RPO LH7 SPARK PLUGS R42CTS VEHICLE "S" TRUCK ENGINE RPO LR2 SPARK PLUGS R43CTS (2) RESET PRIMARY VACUUM BREAK TO REVISED SETTINGS LISTED BELOW BY TURNING ADJUSTING SCREW COUNTER-CLOCKWISE. WHEN MAKING PRIMARY VACUUM BREAK ADJUSTMENT, IT MAY BECOME NECESSARY TO ADJUST (LENGTHEN) THE AIR VALVE ROD TO OBTAIN REVISED SETTING. SEE SERVICE MANUAL FOR INSTRUCTIONS.

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.