I have a 1998 BMW E39 523i that has recently started revving up and down by itself, sometimes to very high rpm. It only does this when the engine is warm, never on a cold start. I've read it could be the idle control valve or the mass airflow sensor, however I don't know how to find out exactly what the problem is. Any advice/solution is greatly appreciated!
Friday, July 27th, 2012 AT 6:59 PM