My 1991 300SE has 125,000 miles on it, and uses about 2 quarts of oil per 1,000 miles. When I get stuck in traffic and have extended idle time (10 minutes will do it), the engine develops a hard miss that will not go away, even at highway speeds.
When the car sits overnight, it is usually fine the next day. Letting it sit for 3 or 4 hours doesn't help.
I supposedly had the valve guides replaced at 90,000, but considering the current oil consumption, it may have been done on paper only. Can worn valve guides cause this type of problem? Any other guesses?
Thanks,
Jim in Norfolk