As I keep saying to people, be sure to check that your timing chain hasn't jumped a tooth and therfore retarded the timing to cause the rough idle. I had the same problems with my '85 380SE last year and after long nights in the garage and lots of money spent on overhauling the fuel injection system (fuel head, injectors, etc..) I decided to pull the valve covers (duh!) and sure enough found the chain had jumped a tooth on the right cam gear and that was what caused the rough idle. That week I brought home a new chain, four new rails and a new ORIGINAL Mercedes tensioner (we've seen problems with the Febi-Bilstein ones) and redid everything. Put it back together and VOILA! Smooth as silk! By the way, I did this all at 110K miles. Also switched to Mobil 1 10W-30 synthetic and hopped in the car the next day and cruised down to Atlanta, GA at 85-90mph the whole way. No complaints so far, of course I recently discovered oil leaks from the right head and the rear main! Time to get those jackstands out!