[Dr Zoidberg]

I dont know the technical name for it, but in the "OLD DAYS" back when cars had a cap and rotor, You would find pitting or streaks of burned deposits on the cap where the spark found an alternate path through the plastic, from the rotor to the plug wire. It would arc through the plastic, due to micro-cracks in the cap due to age or defect.

While changing my spark plugs , on the tip of the # 5 cyl coil/plug assembly ( where the end pushes over the plug) , I notices powder like greyish streaks, that looks just like an arc path ( I know Im crazy but they look like a lightning bolt) , The could be rubbed right off.

It looks like the spark is bleeding out the casing before the plug and going to the head for a easier ground.

I found no other coil packs that looked like it,

Any ideas

Thanks
Geoffrey

[Dr Zoidberg]

Oh so , here is the official name and explanation

Carbon tracking usually occurs because the inside of the distributor cap is dirty or has become coated with oil residue. When an arc occurs it carbonizes the oil and creates a track for the electricity to follow or flow thru, the path of least resistance. You'll see the tracks inside the cap.

Everything seemed pretty clean , but it looked just like carbon tracking ,

Another possible cause I found, since the plugs looked pretty trashed, and the gap was fairly over spec, It was looking for an easier path to ground than the enlarged gap.