I have an 84 528e. The idle speed is a little high. I noticed a vaccum hose disconnected and when I reattached the hose the idle went down. The next day It started doing it again and I inspected my hoses and there does seem to be a little play with the vaccum booster hose but nothing that would seem to cause this rise in idle speed.
Aslo my ICV is working within specifications. Anyone have an idea what the problem is?