My 1988 300E W124 has idle speed problem...when the car is cold, idle speed (when engaged in P or N), it's about 600-700 rpm (which is normal), however, when the car is warm, the idle becomes 1500 to 2000 rpm (when engaged in P or N)!!
My MB mechanic told me that the electronics part of the "air flow volume" sensor (the thing that looks like a diaphragm underneath the air filter element) is defective, however, the actual diaphragm is fine. He told me that I must replace the whole thing (the diaphragm with the electronics part) must be replaced, since they only come together, and the electronics part is not sold separately. The whole thing will cost CDN $700!!
I figure, if the electronics part is available separately, I would save quite a bit of money. Is the "electronics" part available separately? Does anybody have the part number to it?
Thanks very much.