380SE -85. Lost idle at first, then the work done:

-New idle control valve
-New idle control unit
-New throttle switch, replaced a year ago, tested now, almost zero ohms at idle; so it closes, fine
-Temp sensor tested: pulled the connector with warm motor, no change in idle speed, fine
-No significant vacuum leaks

Rpms cold: 750 in D/R, 900 in P/N OK
Rpms half warm: 500 in D/R, 650 in P/N OK
Rpms warm: 550 in P/R, 900 in P/N NOT OK

What can I do now? The repair manual doesn´t help anymore. Take it to the real tech? I appreciate your help!

Here´s what have happened before:

Used idle valve from dealer !

Idle control valve broken?? W126