I read the post on here about adjusting idle. I warmed the car all the way up by driving for a bit, parked it, while running removed the IAC connector. RPM's dropped roughly by a hundred as down to 450 from 550 where its been idling. I proceeded to adjust the idle screw and as i was turning it counter clockwise the car all of a sudden dropped to 250 rpm and didnt adjust at all. While i was adjusting it i turned the lights on which pulled the idle down more, would that be why or is something else the cause like the throttle body?