A colleague at work has a 2002 BMW 318 ISE - it has developed a fault where the engine regardless of wether it is hot or cold will rev up from idle to 2000rpm and then settle down to idle and then rev up to 2000rpm and back down to idle continuously - anyone had this fault or know where the fault may lie - obviously a sensor fault but which one - he has had the fault code read and it is one the BMW dealers gargae dont know of.
Are you sure about the BM garage not knowing the fault code? when cars have irratic tickover i`m pretty sure its down to a faulty MAF sensor but I could be wrong
Could be something different but I had the same problem on my Ford and it was the Idle Valve that was knackered not sure if this could be the same on a BMW though