CEL came on Saturday. Truck had new ACD 41-110s gaped at .040, new tsp wires less than 90 days ago. Probably 6-7k miles now. I bought a new ACD coil day before and seemed ok but CEL came back on. Tonight I pulled the plug and installed a new 41-110 @ same gap.
Any thoughts on old plug?? Looks fine to me based on my research online. Only code present is a P0302
Since those are double iridium plugs, can you show us the ground electrode? Any chance it was damaged when it was gapped?