I was doing the IAC reset procedure, and after I unplugged the valve and restarted the motor, the idle (once I could coax it to idle) was surge between 450 and 1000. Obviously, since the valve wasn't plugged in, it's not suspect. What else could cause this? Fluctuating fuel pressure? I'm not aware of any vacuum leaks.

I do know that my O2 sensor is fouled (bad MAF is making it run rich).

have you fixed your issue? make sure you waited a few secs before unplugging the IAC plug. granted the pentel will extend quite fast its still a good thing to wait. as for the o2, thats a good ques if its a factor in the throttle flux.