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6.0L Spark Plug Gap Discrepancy 0.060 or 0.040??

This is a discussion on 6.0L Spark Plug Gap Discrepancy 0.060 or 0.040?? within the Technical / Maintenance forums, part of the General Discussion category; I picked up an 01 1500HD CCSB with the 6.0L (LQ4 I believe). The truck doesn't get very good mileage. ...

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    6.0L Spark Plug Gap Discrepancy 0.060 or 0.040??


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    I picked up an 01 1500HD CCSB with the 6.0L (LQ4 I believe). The truck doesn't get very good mileage. At times it feels like it's towing a trailer or under load all the time. I scanned it tonight and had no codes either. I am getting about 400 kms to 80L, back roads, no stop and go.

    I pulled a plug tonight to have a look, and it has Declo Platinums, 41-985. They're gapped at .040. The air breather says .060... I looked up the plugs on Rock Auto and they're all calling for .040 and not to deviate from it.

    Can anyone clarify for me what the correct gap is?

    Thanks
    2008 GMC Sierra Z71 Ext Cab
    1997 Silverado Z71 Ext Cab - Stolen, Recovered and being rebuilt

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    Work Hard, Play Harder TheBigBlackHD's Avatar
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    Re: 6.0L Spark Plug Gap Discrepancy 0.060 or 0.040??

    The correct gap is whatever it says under your hood. Alldata says .060. I'd get some new plugs, dont gap the ones you have as platnium plugs you arent supposed to gap (so I've heard).

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    Re: 6.0L Spark Plug Gap Discrepancy 0.060 or 0.040??

    I double checked the plugs with another parts house and they're calling for the plug I have with an .040 gap. I asked about a regular not platinum plug and AC Delco didn't have one I was told. I wanted to put in a regular set at .060 and see if the mileage was better.
    2008 GMC Sierra Z71 Ext Cab
    1997 Silverado Z71 Ext Cab - Stolen, Recovered and being rebuilt

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    Re: 6.0L Spark Plug Gap Discrepancy 0.060 or 0.040??

    this has been posted before...

    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)




    --------------------------------------------------------------------------------

    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.

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    Re: 6.0L Spark Plug Gap Discrepancy 0.060 or 0.040??

    Thanks for posting that information, much appreciated
    2008 GMC Sierra Z71 Ext Cab
    1997 Silverado Z71 Ext Cab - Stolen, Recovered and being rebuilt

 

 

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