gjones8131, if the idle is very rough ... as in considerable engine shaking ... you may want to perform a compression check on all cylinders. I chased a rough idle on a 1995 E320 for months without any success. Finally I went to a local independent tech for a professional diagnosis. He quickly found there was no compression in cylinder No. 1. The tech explained that he had never experienced a valve problem like that in a 104 engine. I distinctly remember the engine changing from running smooth to running rough. Whatever the valve failure was, it occurred instantly. The engine had 198,500 miles on it ... much less than I expected to get out of our "snow car".

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Fred Hoelzle