Originally Posted by sixto

Idle is electronically controlled by EDS (acronyms will drive you nuts). Early 603.96s and possibly .970s have an adjustable trim to set base electronic idle. 603.971s (92-95 US 140s) don't have an adjustable trim. There is a mechanical base idle adjustment on the IP but AFAIK it does not factor into the EDS setting; i.e., EDS will set idle to 650rpm (or whatever) regardless of mechanical base idle setting. Dave can confirm.

Sixto
87 300D