In light of this, I will examine our BW W126 archives for high idle or quick idle.
There is an abundance of information and guidance available.
Vacuum leaks, a contaminated idle air control valve, and a potential failure of the Over Voltage Protection Relay or its fuse.
Best of luck.
My previous issue was caused by a faulty distributor cap, resulting in coil wire arcing and the idle system correcting for the misfire. It is rather sensitive.