1984 380sel. has got high idle in park and neutral i.e. 1500-1700 rpm. When in drive beautiful, around 700 which suits me fine. Any quick checks or fixups.

 

air leak?
dirty idle speed air valve?

 

check over voltage fuse..its the red fuse on top the relay its self ,,if not,,,might be idle air vavle or control unit black box between firewall...sometimes you can rap them with i smell hammer to see if its bad ,,let us now...