I tried and messed with the iacv and anything else i could think of months and months ago, but the idle would go no lower than ~900. I just got back on a round trip from Florida (im in NC). I got home yesterday. Today i realize that my idle is down around 600-700 consistently now, where i tried to get it a long time ago. What can cause this so suddenly? Its fine, i like it where it is now, i feel like this is a good thing , but am curious.

 

There are several things that could have happened:

iacv got clogged a little and got dirty, u used to have an air leak that plugged itself, ecu adjusted...ect...

basically u should check for air leaks in the engine compartment. get someone to rev the engine while u listen for the leak with the hood open...