2001 Won't Idle

My 2001 GS was running fine on Friday. When out to start it on Saturday and it would not turn over. Finally got it started but it won't stay running unless you have your foot on the gas. There are no lights coming on the dashboard. Took it my local mechanic and he was not able to find anything wrong with the car. There are no codes coming off computer either. Any suggesstions?

Check the Idle Speed Control motor. It is easily replaced and fairly inexpensive. Sorta looks like this.
http://usera.imagecave.com/way2old/iac.jpg