Hi Larry! I read your thread regarding gapping your plugs @ .038. Did you make any adjustments i.e. lamda setting etc. to correct up running lean or rich? I have a 1989 300E (Federal) and use the copper plugs called out in my owner's manual. I'm going to try your suggested gap but I would like to know if this creates changes that need to be adjusted for. Thank you Larry! Josies Dad