Take off the IAB and spray,,clean it out with cleaner.Check out the thread at the top of this page about surging idles.It may help,theres alot of good ideas in it
I think he means IAC, Idle Air Control. The motor on the side of the throttle body. One hole before the throttle plate, one after. The motor activates a plunger to open and shut it allowing air in and allowing the computer to controll idle speed. These often get clogged with dirt. Try spraying throttle cleaner through the hole in the TB with the motor revved some. If that fails remove it and clean it. Also check TPS voltage, but first read the sticky at the beginning of the thread.