For 1990-2009 cars

# INFORMATION ON PRODUCTION SPARK PLUG GAP CHANGE

REVISION: 05/08/97

THIS BULLETIN IS BEING REVISED TO ADD CHEVROLET MALIBU TO MODELS. PLEASE DISCARD CORPORATE BULLETIN 77-65-11 (SECTION 6E--ENGINE FUEL AND EMISSION). ---------------------------------------------------------------------- SUBJECT: INFORMATION ON PRODUCTION SPARK PLUG GAP CHANGE

#### MODELS: 1997 BUICK SKYLARK 1997 CHEVROLET CAVALIER, MALIBU 1997 OLDSMOBILE ACHIEVA 1997 PONTIAC SUNFIRE, GRAND AM 1997 TOYOTA CAVALIER WITH 2.4L ENGINE (VIN T - RPO LD9)

A CHANGE IN SPARK PLUG GAP HAS BEEN MADE TO REDUCE SPARK PLUG FOULING DURING REPEATED LOW SPEED OPERATION OF THESE VEHICLES AT ASSEMBLY PLANTS, RAIL HEADS AND DEALER/RETAILER UNLOADING POINTS. THE ELECTRODE GAP OF THE PRODUCTION SPARK PLUGS HAS BEEN REDUCED FROM 1.52MM (0.060IN) TO 1.27MM (0.050IN).

IF A SPARK PLUG IS REMOVED TO PERFORM A SERVICE PROCEDURE AND THE GAP IS FOUND TO BE 1.52MM (0.060IN) AND THE SPARK PLUGS ARE FUNCTIONING NORMALLY, DO NOT CHANGE THE SPARK PLUGS.

ORIGINAL EQUIPMENT SPARK PLUGS WILL HAVE THE PRODUCTION PART NUMBER IMPRINTED ON THE CERAMIC INSULATOR. THE 1.52MM (0.060IN) ELECTRODE GAP SPARK PLUG WILL HAVE A PRODUCTION PART NUMBER OF 25164044 AND THE 1.27MM (0.050IN) ELECTRODE GAP SPARK PLUG WILL HAVE A PRODUCTION PART NUMBER OF 25312636. THE SERVICE SPARK PLUG PART NUMBER FOR ALL 1997 LD9 ENGINES IS 25164048 WITH AN ELECTRODE GAP OF 1.27MM (0.050IN).

#### IMPORTANT: DO NOT MIX SPARK PLUGS WITH DIFFERENT ELECTRODE GAPS ON THE SAME ENGINE. IF IT BECOMES NECESSARY TO CHANGE A SPARK PLUG IN ANY OF THESE VEHICLES EQUIPPED WITH SPARK PLUGS THAT HAVE A 1.52MM (0.060IN) GAP, REPLACE ALL FOUR SPARK PLUGS WITH GM PART NUMBER 25164048 WITH THE ELECTRODE GAP SET AT 1.27MM (0.050IN).

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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.

COPYRIGHT 1997. GENERAL MOTORS CORPORATION. ALL RIGHTS RESERVED.