I have a 1984 BMW 318i that has started idling at an extremely high RPM around 3,000 to be exact. I can tap the gas and the idle will go down momentarily, then it will sputter then it picks back up the idle speed to 3,000 RPM's and remains there. I had thought about starting with the Idle Air Stabilizer Valve. Anyone have any ideas or is this a good place to start. Thanks.