Check the Idle speed controller.
This is located on the Throttle Body, and is used by the Computer to control the Idle speed.
Basically, the Plunger on these things can get blocked up, (Especially If you have an aftermarket Oil based Air Filter), and If the Plunger sticks, then it is quite common for the Car Idle to be All over the place.
(Mine was revving out on 2-1 Gear Changes, and a couple of months later after puliing out from my home, the car started Idling around 2500 RPM at the first stop light I came to.
Check out
http://www4.tpgi.com.au/users/mij/Au.../Problems.html
For more Info on how to clean this thang.
Basically this is the same one that is used on EA-EL-AU Models, but because the Intake Runner Layout is different, the ISC is located in different places.
Cheers
Matti