I recently aquired a 1985 BMW 318i.  It will not idle properly.  When
the engine is not in gear and moving, the engine will jump constantly
between 900 and 1100 RPMs while idling. Everything else seems to be
running properly.  Someone told me that the idle control unit needs to
be replaced.  Do you think this correct?  I have heard that there is an
idle control valve; this is not the problem?  I cannot locate the idle
control unit.  Someone told me that it is located in-between the glove
box and dash, but I can't find it.  Will someone provide me with
detailed instructions or a diagram?  I cannot afford a mechanic and am
not savvy with cars.  I cannot afford a manual, but wonder whether or
not this information is provided in the Bentley manual.