Anyone that goes out and spends more than $2.50 on a plug needs to wise up.... you are NOT make more power, getting better mileage or anything else with those $8+ plugs than you can with a cheap ass Copper MotorCraft.
I got a good question. My check engine light was on, saying #3 misfire. I did a tune up and a week or 2 later it came back on. So I upgrade plugs and it was gone for about a month or 2 now its back, anyone know whats going on. Next step is trying the NGKs and MSD coil with massive wires.