In our 190E, remove the injector lines, the EHA and potentiometer connectors, the pressure regulator, and all other fuel lines that connect to the fuel distributor. Loosen the clamp at the throttle body. Remove the bolts attaching the airflow sensor to the intake manifold runners, and lift off the airflow sensor / fuel distributor assy as a unit, disconnecting the idle air valve inlet line as it becomes accessible. Keeping the two bolted together should help minimize tedious setup procedures.
This is a good time to replace all the rubber hoses in the idle air / breather system, as well as the rubber lower plenum of the airflow sensor - if they have age hardening.
'91 MB 190E 2.3
'08 RAV4 Ltd 3.5
'83 Lazy Daze m'home 5.7