1989 Mercedes Benz 420sel

Engine Performance problem
1989 Mercedes Benz 420sel V8 Automatic 150000 miles

the engine idles at 2200rpm in drive. In park it will go as high as 4500rpm. Had this problem start about 6 months ago and I sprayed carb. With carb cleaner and it then ran fine until now. I tried spraying carb again but no luck. Any ideas
Albert tabus
July 1, 2009.

Can you cover the throttle body with your hand to see if the idle will drop down.

If it drops down you can rule out a vacuum leak.

Can you see the throttle plate, how far open is it?

Is something blocking the plate from closing?

Jul 3, 2009.