I have read in 103 Mercedes Literature [the service manuals and CDs, I believe] that the engines tend to idle more smoothly with the EHA disconnected. They go on to say there is no known cure, it's just the way they are. It was in the "programmed operations" section or something like that.

Both our 103s have a bit of rough idle; both are the same.

I drove a friend's 104 on a trip last weekend and you could not feel it running at all.

Maybe the difference is the KE vs the HFM fuel injection.

__________________
2012 E350
2006 Callaway SC560