You must be loosing oil some time. You can't have an oil soaked plug and not be burning oil in that cylinder. The engine has a problem. Might well be a valve seal, it could also be a valve guide. It has to be some where. I would say valve seal. Engine speed, or hard driving has little to do with it. I would think the quickest build up of oil on a plug will appear with slow easy driving. Hard driving will leave a charred residue.

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Junqueyardjim
Christianity, if false, is of no importance, and if true, of infinite importance. The only thing it cannot be is moderately important. C.S. Lewis



1983 Mercedes W123 240D 4 Speed 285,000 on the road with a 617 turbo, beautiful butter yellow, license plate # 83 240D INDIANA

2003 Jaguar Type X, AWD. beautiful, good mileage,
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