Thanks for the help thus far everyone.
I took a closer look at the IAC valve and throttle body. The IAC did look to have some carbon buildup that could be preventing it from functioning properly, but I didn't have a chance to get a picture of it.
I also removed the air intake from what I believe to be the throttle body (don't know much about what I'm doing, but going off of the help here as well as searching Google) and it looked clean to me (see attached...)