We both seem to have read that wrong. You said ISC, not IAT. The ISC (idle speed control) valve lets air bypass the throttle body's butterfly at idle. The butterfly is closed at idle, so the air needs another way to get to the intake.
There isn't much relation between them other than the fact that air flows through each of them.
I ask this because I'm having this problem with my car (Kia Sephia 96 GTX 1.5). When my car is idle (but the engine is on), i.e. when I'm waiting for the green light at a traffic light, I start to hear my car accelerates itself (I can even see how the rpm meter moves up and down). it's just like i'm pressing and releasing the accel pedal, and it keeps on and on till my car stops.
by asking to some friends, I was told that disconnecting and reconnecting the MAF could solve the problem temporally, and it really works, but after 2-3 weeks the problem reappears. I took my car to a mechanic and he said it was the ISC valve the problem.
As you can see, reconnecting the MAF solves the problem, but , according to a mechanic, the problem is in the ISC valve. Any ideas?