Originally Posted by Megan370z

the screw is set at factory and loctited there very hard with a jam nut

then yeah you can set the idle tru the ECU.

but having it bored out, you have more air comming thru the plate because the butterfly still close at the same angle but its now bigger.
it doesnt take much to affect the idle air flow speed..


look at this picture , the jam nut on the idle screw is located on the bottom left and right of the TB.


hope thats help to understand