I recently purchased a 1995 E300 with 95,000 miles. It has a high idle speed in Park, around 900 RPM. Normal drive idle is about 600 RPM. What can I do to fix this? Is it controlled by any of the throttle linkage rods? I notice the rod across the valve cover slides around like one side has free play, is this normal?

I have a 1987 300D that I'm fixing but this 1995 E300 is so new to me, any advise is appreciated.

Thanks,
Brian