changing the coil to plug boots cured this exact problem for me. misfire diagnosed on #6 cylinder. check engine light never went on.
Same for my car. See my signature below. One cylinder was misfiring because of a bad boot on one cylinder.
2001 E430, Bourdeaux Red, Oyster interior.
1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".