The idle adjust screw is located on upper portion of throttle body. It could have worked itself loose if any adjustment had been made before. The diagram is not the exact one for your vehicle but it shows the location.
When idle speed increases, it is caused by excessive air getting into the intake manifold so you should check :
1. Clogging of the coolant hoses of IAC would result in same problem. Coolant might be present, but did you test if they were clogged? Remove the hose and apply low pressure to each side and reconfirm.
2. Check the Fast idle valve, next to IAC. Remove the air cleaner hose. Warm up engine and with finger, test the upper port of the throttle body for vacumn. If vacumn is high, the Fast Idle valve is not closing fully. These valves tends to work themselves loose. Remove the 2 screws holding the cover and check the white plastic position. It should be seated with about 2 threads visible at the side of the internal housing.
3. Check PCV on top of valve cover.
4. If the brake pedal seems stiff at times, check for vacumn leakage at the seal between master cylinder and booster.
Thursday, April 30th, 2009 AT 8:28 PM