JNT, Avatar, Cool, and a GREAT BUNCH of OTHER RESPONDENTS to my NEED regarding the IDLING PROBLEM on my 1991 560SEL - Car is fixed!!!! Here is what happened: Checked and have had tested ALL recommendations provided, smoke test, plug wires, plugs, compression, EHA and potentiometer settings - everything checked out O.K. However, I read another rough idling problem at the forum, and it was mentioned that THE ENGINE MOUNTS (I think this is what they were called) BE CHECKED FOR WEAR. Instructred my mechanic to do this, and I was assured that it would not be the problem. Well GUESS WHAt!?!, the mounts were approximately 50% worn on the right side and about 60% on the left side. I had the new mounts installed, and the idling problem is NO LONGER. I owe you GUYS a HEAP OF THANKS.
Forever Grateful!!
kilyab