I covered the end of the idle stabilizer control valve with tape so that no
 air could pass through that system and reconnected the hose coming from
the air  intake boot.  I started the engine and the van idled at a normal
speed,  about 950 RPM.  How do I determine if the idle valve is at fault or the
control unit is at fault?  How much air pressure should the valve resist
before opening (so as to determine if the internal spring is weak and causing
a  leak)? And how do I measure the control unit to determine if the correct
current  is being applied to the valve(so as to determine if the control
unit is at  fault)?

Thanks,
Rico Dagastino
Memphis, TN