Before you guys fuss at me for not searching, I did, I really did. I found my two issues addressed separately, but together I am wondering if it could be something else.

1989 560 SEL 172,000 miles. Idle in park and neutral is about 1300-1400. In gear, drops to 700 or so and develops an intermittent 'roughness' and for some reason, seems to be rougher in reverse. Car runs great, just stopped at a light with foot on the brake, it gets rough.

I did try an idle control module from a salvage car, plugged it in and no change in the high idle in park, so I did not replace that.

Any suggestions/ideas are appreciated.