325 Fast Idle

I have a 1986 BMW 325 with an automatic transmission. I started it yesterday after several weeks of being parked. The engine immediately revved up to 2,000 rpm and stayed there. I tried to kick it down with the accellerator pedal but it keeps racing. I put it in gear hoping that would slow it down but it still runs so fast that I can barely stop the car with the brake pedal. How can I fx this problem? Is it electrical or mechanical? Any help would be appreciated.

Jim Mahoney

It is possibly the throttle switch. There is a micro switch that is located on the back side of your intake maniflod, between the motor and the bottom of the intake. It is probably bad and making the DME think that you are off of idle and the thing is freaking out not knowing where to go. Or another possibility is you Idle Valve. There is a silver cylinder looking thing in between your airbox/vane airflow meter and your throttle body. It connects to the hose in between the two. Tap on that cylinder thing called the idle valve and if your idle comes back to normal than it is bad. Meaning it is stuck in a wide open position and feeding alot of air to your engine, unmetered by the throttle blades. Check here first actually