> The Idle control valve:
> - Is simply a fan that pumps air into the center plenum.
> -The volume is metered by the airflow meter.
> -The volume is determined by the idle control module.  The
increase or
> decrease in speed based on out puts from various sensors.

i have to disagree here ...

the idle stabilization valve
- is not a 'fan' ... it's a solenoid that pushes open/close a
small valve.
- the air permitted to pass through the valve is NOT metered.
look at the hose connection ... the hose from the valve connects
between the throttle body and the air flow meter:
downstream/after the metering of input air.
- the NEED for air is determined by the idle control module,
based on several sensors. the module tells the valve to open or
close, depending on whether the idle needs raising or not ...
like when you have the a/c on at idle, or when you are turning
into a parking place (power steering) at a slow speed.

to quote the vw digifant diagnosis book ...
" Idle stabilization valve -
electronically controlled valve used to maintain idle speed at a
pre-determined level by regulating intake air at idle.
location: rubber mounted to top of intake air distributor"

the rough equivalent on the digijet fuel system would be the aux
air regulator.

joel