Gents, My 95 C36 suddenly developed a peculiar idle today. It fluctuates from 1000 to 1700 RPM in approx 1-second cycles, in gear or in neutral. This is scary because the car speeds up by itself when the RPM climbs and brakes can hardly hold it.

I shut the motor off but the problem was still there when I re-started. I shut it down once again and when I fired it up after a couple of seconds, the idle was now steady but very low (400-450 RPM). There are no check engine lights showing and everything else seems normal.

I did a search but can't find any posts with these particular symptoms. The plugs are about 1 year old (less than 15,000 km) and car is very smooth and powerful until today.

Assistance in troubleshooting this malady is highly appreciated.