Anyone do plug checks in combination with their A/F readings?
Since lead additives in gasoline got eliminated by the tree huggers, plug checks are pretty much a waste of time. The "tan to chocolate brown" we used to look for 50 years ago has literally been replaced by "black and white". Way rich is sooty black, and virtually any other mixture doesn't do any color change until extremely lean conditions start to glaze and blister the ceramic, and the ground electrode starts to burn away. What we were looking at back in the dark ages was varying degrees of lead deposits making the surface of the porcelain change color.
Jerry
