I know this has been posted about a lot but I'm stumped. I did a diagnosis based on the cd and determined the ICU was bad. So I replaced a few transistors tht were bad and it held the idle for a while but slowly over time high idle again. So I bought a used icu from my Benz part guy I go to and it worked for about 10-15 min and the idle went bad again. So this last time I checked all the diodes on the board, they seemed good, and replaced all electrolytik caps all ic chips and all xistors. Once again same problem. I'm stumped. I really doubt this prob is based on a faulty diode or cap tht I didn't replace but I suppose itds possible. Ideas?