Car is an 89 420SEL with 180,000 miles.

The car is idling a little high at around 1600 rpm. I swapped the idle speed motor out of another car and no difference.

By removing the air cleaner and pulling up on the throttle plate, to restrict more air, the idle drops down to normal. Throttle plate seems to be vacuum actuated. I have looked for vacuum leaks and did not find any obvious ones.

Also, what are the air conditioning lines that run to fuel distributor for?

Thanks