8.1 Spark Plugs Ac Delco Problem

cbmind · October 11, 2009

Picked up some Delco 41-983 plugs all gapped at .060 the other day for my 8.1 silverado, 2001. Put them in today. Change plug wires too as the old ones were destroyed pulling them off. Anyway, fired it up, extremely rough idle, 2 minutes or more into idle service engine soon light comes on. Any ideas? Pretty sure this is the right plug. Old ones looked like crap pulling them out. Truck has 270k on it. Thanks. Searched, couldn't really find what I need.

dlstewart01 · October 11, 2009

Don't know if this will help, it doesn't mention 8.1. What codes did you get, sometimes the boot will not be on good enough and you will get a missfire. The code will tell you what cylender it is on.

Subject: Information on New Spark Plugs and Gapping #03-06-04-060 - (10/24/2003)

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 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 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)

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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 1.01mm (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.

GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these 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 your GM dealer for information on whether your vehicle may benefit from the information.

WE SUPPORT VOLUNTARY TECHNICIAN CERTIFICATION

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Document ID# 1396703

thearborbarber · October 11, 2009

The iridium plugs can be damaged f you try to move the gap around. Another area would be to make sure the plug wires are on all the way. Make sure they "click" into place on each plug. Sometimes they can be a real bear cat.

cbmind · October 11, 2009

Picked up some Delco 41-983 plugs all gapped at .060 the other day for my 8.1 silverado, 2001. Put them in today. Change plug wires too as the old ones were destroyed pulling them off. Anyway, fired it up, extremely rough idle, 2 minutes or more into idle service engine soon light comes on. Any ideas? Pretty sure this is the right plug. Old ones looked like crap pulling them out. Truck has 270k on it. Thanks. Searched, couldn't really find what I need.

Sometimes I have a special moment... well one spark plug wire seems to not have been hooked up properly. Don't know what it was on, but it wasn't the spark plug... Anyhow, works great. Great forum here, Lots of info. Thanks, goes to show you not onlydouble check you're connections, but triple check too!