JOEL if you find out what the problem is please let us know here because I have the same problem on my M102 engine. I thought it might be the bowden cable which looks a little slack below the throttle cable. The throttle cable itself feels fine. I am thinking of replacing the throttle switch like Benzmac suggest, failing that i'll have to visit MB.
p.s. Try tapping the accelerator pedal slightly several times and see if the idle sinks.
88 230e (W124)
[This message has been edited by yal (edited 01-07-2000).]