Fast Idle Problem Cured!
 

What an expensive education. Trying to repair a constant high idle(1500-200rpm's) in my 1983 380SL, I replaced the idle control valve, the idle control unit, and the over voltage protection relay. The problem still wouldn't go away. I finally replaced all 8 fuel injector and injector socket seals and the problem vanished. Hope this helps someone else. By the way I have all the parts listed above for sale in the swap shop classified section. They were posted on 11/06/01 under 1983 380SL fuel injection parts. All removed parts are guarenteed to be in working condition.My e-mail address is billywhitesides@aol.com

I am glad to have read this.

The 124 we have has constant high idle and despite doing all that you've done, the problem has yet to be solved. The high idel kicks in mostly when the engine has been running though not extremely hot.

I have already decided to change the injectors for both the 126 and 124 and monitor its progress from here.