I did replace the IACV (Idle Air Control Valve) and the TPS (Throttle Position Sensor). But it sounds like the Idle Air Control Sensor is something different, and I haven't taken a look at that one yet.

A few months ago, I'd never heard of any of these things. At least now I have a basic understanding of what they do. Hopefully this one won't be too much for an automotive illiterate like me to handle.