Q&A

 Master

You may need to repalce the Idle Air Control (IAC) valve or maybe just clean it if it's full of carbon. There may be something else involved so I can't say for sure what's wrong but if it's the IAC itself, it'll take about an hour to replace it and check diagnostics to see if it's fixed.
The IAC part will cost you abut $160.
Here's a directory link for you:
http://repairpal.com/directory?address=23234&car_brand_na...