When I start-up my '86 325e it idles really fast up to around 2k then comes down to idle speed around 1k all in about a matter of a sec.?? any suggestions?

if when u start it up it goes up to near 2k, then goes down to about 700rpm right away, then it is normal.

otherwise, it may be the idle control valve or carbon build up, or. . . it can be many things. try out the technical articles at bmwe30.net for more help.

its not unusual for cars to rev up abit before returning to idle. i think it has something to do with trying to build up the temperature fast. if it returns to idle in a matter of secs its ok.