Berto,

That plug of yours looks like it has a bit more carbon that would be expected on a normally running cylinder. I'd expect to see more grey/brown than black and flaky.

 

Well, that's the thing--it actually is textbook gray/brown. I fooled with the camera white balance and color saturation to make the photo look like the plug really does. No luck.

It does a little bit or erosion down on the base, which I wouldn't expect to see. Otherwise, it's in good shape.

--Paul