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  1. #1

    Default Spark plug reading?Are you a plug whisperer?

    I changed out my plugs today and was curious if the markings on them mean anything. I have pulled oily plugs, really worn plugs, and so on from other vehicles, but am never good at identifying an issue unless it is major. I have one I saved from a 2002 explorer where the lead was worn down to a knife edge and the electrode was almost completely gone. On these, the lead looks pretty white from where it connects to the plug to the bend, the area of the lead after the bend looks black/brownish. could be normal. it is not very often that I get to pull "normal" plugs, most the time they are when someone brings me a car that has gone double recommended change mileage. thanks

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    Last edited by Pikey; 02-06-2014 at 05:48 PM.

    1995 Silverado 4x4
    6" BDS Suspension Lift-3" Body Lift-Add A Leaf in rear -Trailmaster SSV Shocks-Duel Steering Stabilizer Kit -AirAid Cold air intake-
    4.56 Gears with Detroit Auburn Locker-Pro-Comp Traction Bars with duel shocks-Aluminum Skid Plate Kit-38.5" x 16.5" Mickey Thompson Baja Claws-Constant Dropping fuel gauge

    2005 Yukon XL Jet Power Programmer, Bilstein Shocks, Bilstein rear springs, Helwig Anti-sway bars, EGR Window Visors, EGR Hood Shield, Denali Headlights, Headlight harness upgrade, GE NightHawk Bulbs, White Night Rear lighting system, Russell Braided SS brake lines, PowerStop Brake pads, PowerStop cross drilled and Slotted Rotors,
    2002 Silverado ext cab 2wd (Sold)
    2003 Yukon XL (Totaled)

  2. #2


    Like you Mike, I have trouble reading "good" plugs, but they look like everything is working as it should.

    '09 Avalanche LTZ - Black
    '05 Envoy XL (sold)

  3. Thanks Pikey thanked for this post
  4. #3


    Quote Originally Posted by RayVoy View Post
    Like you Mike, I have trouble reading "good" plugs, but they look like everything is working as it should.

    cool! Thanks for the response ray. I have a chart and it says white indicates that it is running lean or too hot. but, that shows the entire lead white, not just part of it and the tip black/dark brown. I ran a programmer on it for a while, but have since removed it to diagnose some odd noises I was getting. I am pretty sure that they are the original plugs, the dealer that I bought it from put new wires on it. But, the plugs i pulled are a number that they stopped making in 2009. I figure that the dealer would have installed the new part number. They don't look too bad for 160,000 miles. The gap was still good.

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