While we're here, let's clear up a few misconceptions ...
Closed loop operation on EEC-IV vehicles is only acheived after the EEC has run through the startup fueling logic and, on the applicable strategies, the coolant temperature (as indicated by the ECT sensor) has reached a certain preset point (also referred to as the "stabilized ECT temperature"). That said, simply disconnecting the MAF will not "force" closed loop operation on any EEC-IV vehicle.
Disconnecting a properly-functioning MAF
will, however, trigger a portion of what is commonly known as the "limp home" mode logic and should cause the engine to run rough at all throttle modes, as Rockledge has noted. Moreover, while the EEC is operating in this "limp home" mode (also known as Limited Output Strategy in EEC circles), it will stop looking at certain sensor inputs for it's calculations (sensors that would normally have feedback during closed loop operation) and default to open loop operation for engine fueling, relying heavily on certain pre-programmed parameters and tables for it's calculations. Once the proper sensor inputs have been re-established and the EEC is satisfied that these signals are within the proper range, it will discontinue "limp home" mode and resume normal operation.
As for your IAB, Hamal, I would recommend that you pull your voltmeter out and subject that sucker to some diagnostic testing. In my experience, I have found that any IAB that doesn't **** a running engine once you pull it's connector either has a stuck (open) valve or air leak somewhere else in the upper intake (as Kenny and Rockledge have both suggested).
