Thought the nut was loctited on to the shaft , and you did not touch it , would not want that nut coming off and going for a wander into engine ....ouch.......I always adjusted the base idle with the air bleed screw , different people have different ideas how to do this , I always did them hot with no load on and fans off to about 850 , then the ISCV only comes into play for cold start and other load situations like fan on , make sure TPS is calibrated correctly and someone has not adjusted the base idle using the TPS as the back stop for throttle plate, go back to basics , check each sensor for correct base readings , would offer to came and have a look but it is a bit far