1998 BMW 328 Engine searching for idle

amjackso · Posted at Fri Jan 04, 2008 6:42 am

Engine problem
1998 BMW 328 6 cyl Wheel Drive Type unknown Manual 83000 miles
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We replaced the SECONDARY AIR PUMP & VDO Air Mass Meter. The car ran fine for a few days but had a low idle. We manually adjusted the idle. Once again the car ran fine for a few days. Now the car is searching for an idle. Hand held diagnostic shows no code as the check engine light is not on. Can you tell me what part is going out?

Dr. Hagerty · Posted at Fri Jan 04, 2008 8:59 am

When you say you manually adjusted the idle what did you do exactly. If you moved the throttle plate by means of the small adjusting stop, you need to move that back and if the idle is too low, then the idle can be adjusted up electronically with the BMW software from the GT-1 version 37 or 39. What may have happened is the throttle plate sensor is fixed and has two potentiometers that work on a 5 volt reference, when out of adjustment it can make the idle speed can "hunt" around. Also, what is the history on the service for the car?