my engine surges up and down a bit when setting minimum air. i was wondering if this is normal. if not then what could cause it? my IAC is new.

also would it help if i set it a lil higher than normal with the intake mods i have? my car is idling at around 600 rpm right now in drive.

thanx

 

Checked for vacuum leaks? all the hoses and hard lines? A small vacuum leak will be more noticable at lower RPM's