Jump to content


This topic is now archived and is closed to further replies.

Recommended Posts

Subject: Information on New Spark Plugs and Gapping



Models: 2004 Buick Rainier


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, SSR, TrailBlazer


1999-2004 GMC Sierra


2000-2004 GMC Yukon, Yukon XL


2001-2004 GMC Yukon Denali, Yukon XL Denali


2002-2004 GMC Sierra Denali


2003-2004 GMC Envoy XL


1998-2002 Pontiac Firebird


2004-2005 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, LS1, LS6, LQ9, LQ4)




Attention: Please disregard the Set Gap Per Vehicle Specification statement on the side of an ACDelco® Iridium Spark Plug Box. The statement will be removed from the boxes in the future.



• 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 in) when the spark plug is made.



Notice: 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.

Share this post

Link to post
Share on other sites


Important Information

By using this site, you agree to our Terms of Use.