idle problem with e36

[Davíð Freyr Jónsson <DFJ1@xxxxx>]

hi digester, 
(newbiee)
I'm asking for a friend of mine who has a e36 325i with idling problem.
it revs from 500 to 1500 rpm cold or hot.
can he adjust the rpm himself or is it some bad sensor? could it be the
oxygen sensor?
anyway thanks for any input.
I have a older BMW a e21 323i '82 lowered by 2" and the car have Zender
spoiler kit.
you can email me at dogh@domain.elided to get some photos.

------------------------------