Spark Plug: Technical Service Bulletins Ignition System - New Spark Plug Type/Gapping
Bulletin No.: 03-06-04-060
Date: October 24, 2003
INFORMATION
Subject:
Information on New Spark Plugs and Gapping
Models:
2004 Buick Ranier
2002-2004
Cadillac Escalade, Escalade EXT
2003-2004
Cadillac Escalade ESV 2004
Cadillac CTS-V
1997-2004
Chevrolet Corvette
1998-2002
Chevrolet Camaro
1999-2004
Chevrolet Silverado
2000-2004
Chevrolet Suburban, Tahoe
2002-2004
Chevrolet Avalanche
2003-2004
Chevrolet Express, TrailBlazer
1999-2004 CMC Sierra
2000-2004 CMC Yukon, Yukon XL
2001-2004 CMC Yukon Denali, Yukon XL Denali
2002-2004 CMC Sierra Denali
2003-2004 CMC Envoy XL
1998-2002
Pontiac Firebird
2004
Pontiac GTO
2003-2004 Hummer H2
with 4.8L, 5.3L, 5.7L or 6.0L V-8 Engine (VINs V, P, T, Z, G, S, N, U - RPOs LR4, LM4, LM7, L59, LSI, LS6, LQ9, LQ4)
A new spark plug has been released for use in the above vehicles. The new spark plug has an Iridium tip instead of the current Platinum tip. Due to the different tip design, the gap of the spark plug has also changed. The new spark plug, P/N 12571164 with AC Delco P/N 41-985, is gapped to 1.01 mm (0.040 inches) when the spark plug is made. The spark plug gap is set during manufacturing and should not be changed or damage to the spark plug may result. Any new spark plug found to not be properly gapped should not be used.