I have a 2007 cobalt with about 87,000 miles. Check engine light is on. My cobalt is make a whinning or mumming noise from the engine and is idling high. It is about 1rpm's just setting and when I crank it up. The noise gets louder when I drive it.

 

Take it to autozone and get it scanned.. would be helpful if you could post up the code its throwing