1998 BMW 328

Engine Mechanical problem
1998 BMW 328 6 cyl Two Wheel Drive Manual 49000 miles

When the engine warms up to normal it will start to rev too approx. 3000rpm then go back too normal idle rpm ( 900 ) then back up to 3000 then back to normal. Up. Down. Up.
March 6, 2009.

There is a vacuum leak. Probably the air intake boot, inspect for tears or ripped areas.

Dr. Hagerty
Mar 6, 2009.