Hanson. Had the similar rough idle and hesitation at lights on warmed engine- 1985 380sl. Changed filter/accumulator and also ran full can of Seafoam and Italian tune-up. Car runs perfectly for last 6 months. It was somewhat underused since it was a car my son used daily until 2 years ago when his job moved him out of state. As a do it yourself-er, my philosophy with older cars is to use simple fixes before going in big. Good luck.