does the ECU control the idle?

 

Yes it will adjust it up and down to achieve target idle, but the closer the ICV is at it's base setting the better. Logging in Evoscan steps at idle should be between 20 and 50.
You'd be surprized at the amount of cars with ICV's out of adjustment, when you hook Evoscan up and park the ICV.

 

Idle fixed! After installing the IACV the car idled low, so I had to tinker with the throttle cable.