Jim, thanks for your response. I switched to NKGs at Robby's suggestion. Today when I drove to my daughter's soccer game, I thought "this car has gremlins - it's running like crap today" after a flawless week of driving. After leaving the game, I drove down a winding, hilly country road and gave it the old "Italian Tune Up", and sure enough, the missing went away. Could I be getting deposits on the plugs causing the electrodes to short out? I'm going to pull a plug or two tonight (hopefully...) when I go out to put some more sunroof lube together for shipping to Mercedesshop members! I'm just wondering if I should try a hotter plug? Or, the other problem I have it that it's about 1-1/2 miles out of our neighborhood before I can really run the car. So, it spends a LOT of time at idle and/or slow speed. I'm rambling...

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Bill Streep
San Antonio
'57 190SL (toy)
'08 S5500 (mine)
'09 CLK550 (wife's)
'06 SLK350 (daughter's)
'11 GLK350 (daughter's)
'03 CLK310 (spare)