Vehicle: 2007 Chevrolet Silverado 1500 New Body (6.0L L76 V8 with AFM).
Primary Issue: Persistent Cylinder #6 misfire accompanied by severe high-voltage ignition arcing under the hood, severe EMI/static in the audio system, surging idle, and transmission shifting hard due to low voltage.
What Has Been Tested & Ruled Out:
#6 spark plug, plug wire, and ignition coil have all been replaced or swapped with known-good units, but the misfire remains anchored to cylinder #6.
Electrical testing confirms the #6 coil ground is solid at 0.6 ohms to the engine block, and the pink power wire delivers ~11V with the key ON.
Potential Root Causes Being Investigated:
Melted Capacitor / Sub-Harness: The integrated radio noise suppression capacitor / shared splice block molded into the passenger-side ignition coil sub-harness (near cylinder #6) is visibly melted and burnt dark brown, which is a prime suspect for shorting the shared 12V/ground feed and causing the wandering high-voltage arc, voltage drop, and EMI noise. But unfortunately I don't have the knowledge to know if this is truly a possibility.
Mechanical/Valvetrain: Potential Active Fuel Management (AFM) lifter failure on cylinder #6 but dosent explain the stray voltage.
-Thanks much
