by ATAl » Wed Mar 30, 2011 6:28 pm
First is the iscv valve working properly - it's the one with an air hose running into the top of the intake manifold right near the head. This controls the idle speed normally.
It's possible the throttle bodies are adjusted incorrectly and are letting through more air than the iscv valve can compensate for. To adjust the throttle bodies remove the plenum, then there are small screws on the end face of each throttle body, screw these in to decrease idle. It's probably a good idea to screw them in the same amount each as otherwise you'll get the throttle bodies out of balance.