How To Test The COP Coils (GM 4.8L, 5.3L, 6.0L, 8.1L)

TEST 8: Carbon Tracks And Other Stuff

Carbon Tracks Causing A Misfire. How To Test The COP Coils (GM 4.8L, 5.3L, 6.0L, 8.1L)

You've reached this test step because there's a good possibility that the misfire, that your GM vehicle is experiencing, isn't due to a bad Coil-On-Plug ignition coil. This section will delve into other possible causes.

One of them is carbon tracks. Carbon tracks are one of the leading causes of misfires. This condition usually occurs on vehicles that have over 100,000 miles on them and is a result of lack of maintenance (since the spark plugs and spark plug wires should have been replaced at this mileage or before). Of course the spark plugs and spark plug wires should perform flawlessly for one hundred thousand miles (100,000) theoretically speaking (I never learned to speak Theoretical). But this doesn't really happen in real life.

So, to make the long story short (you're probably already getting eye-strain from reading this article), you should check for carbon tracks on the spark plug wires and the spark plugs. In the photos in the image viewer, you'll see what they look like. Below are other suggestions to look into:

  1. Low engine cylinder compression in one or more cylinders.
  2. Bad fuel injectors.
  3. Leaking intake manifold gasket.
  4. Fuel pressure regulator gone bad and leaking fuel into its vacuum hose. I SEE THIS ALOT!!!!.
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Buick Vehicles:

  • Rainier 5.3L
    • 2004, 2005

Cadillac Vehicles:

  • Escalade 5.3L, 6.0L
    • 2002, 2003, 2004, 2005

Chevrolet Vehicles:

  • Avalanche (1500, 2500) 5.3L, 8.1L
    • 2002, 2003, 2004, 2005

Chevrolet Vehicles:

  • Express Van (1500, 2500, 3500) 4.8L, 5.3L, 6.0L, 8.1L
    • 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006
  • Silverado (1500, 2500, 3500) 4.8L, 5.3L, 6.0L, 8.1L
    • 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006
  • Suburban (1500, 2500) 4.8L, 5.3L, 6.0L, 8.1L
    • 2000, 2001, 2002, 2003, 2004, 2005, 2006

Chevrolet Vehicles:

  • Tahoe 4.8L, 5.3L
    • 2000, 2001, 2002, 2003, 2004, 2005, 2006
  • TrailBlazer 5.3L
    • 2003, 2004

GMC Vehicles:

  • Envoy 5.3L
    • 2003, 2004

GMC Vehicles:

  • Savana Van (1500, 2500, 3500) 4.8L, 5.3L, 6.0L, 8.1L
    • 2003, 2004, 2005, 2006
  • Sierra (1500, 2500, 3500) 4.8L, 5.3L, 6.0L, 8.1L
    • 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006
  • Yukon 4.8L, 5.3L
    • 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006

Hummer Vehicles:

  • H2 6.0L
    • 2003, 2004, 2005

Isuzu Vehicles:

  • Ascender 5.3L
    • 2003, 2004, 2005, 2006