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2006 GMC Envoy Denali 5.3L Cylinder 6 Misfire: Diagnosis and Fixes After Spark Plug and Coil Pack Replacement

Model: 2006 GMC Envoy Denali Fault Code: P0306 Posted: 2016-05-12 16:47

After performing an oil change and spark plug replacement on my 2006 GMC Envoy Denali with a 5.3L V8 engine, I began receiving a cylinder 6 misfire diagnostic code. I replaced the coil pack and swapped the spark plug wires, but the issue persists. The vehicle still shows a persistent misfire in cylinder 6. Any insights or troubleshooting steps would be greatly appreciated—especially regarding potential causes like faulty spark plugs, ignition components, or internal engine issues related to cylinder 6.

Related fault codes
P0306
Comments (1)
Anonymous 2016-05-12 17:45

Did you remove the spark plug from cylinder 6 and inspect the gap? It's possible that during installation, the ground electrode was pushed too close together, leading to poor ignition performance and misfire.