high idle

Sounds like your idle control motor is defective. here is an online repair manual source so you can see what you need to do. http://bit.ly/mitchell_repair_manuals_online

Likely you have a failed throttle position sensor. Pay a mechanic to replace it unless you want to become an expert and learn how to PROPERLY adjust a new one. It's very hard to access the two tiny screws that hold it in and very easy to drop them. Suggest you replace with allen heads & use a ball driver.