I still think you have a problem personally....

If the idle valve was actually open all the time due to missadjustment, then unplugging it would do what to your idle speed?

NOTHING AT ALL.

It sounds to me that you have a duty cycle being applied to your valve by the ecu.. when the system is working perfectly, there is NO operating current at the connector, hence plugging it on and off does nothing.

At least all appears sound now mate, lets hope you havent just masked the problem by adjusting the valve to need more current than normal to open it though.

EXAMPLE:
With the crank sync error code you are now getting.. you SHOULD have a high idle speed.... after your adjustments.. you do not.....