For some reason, the idle on my car is completely goofed up. When I crank it up in the morning, my car sometimes idles at 600rpms, and other times it idles at 1500rpms. Then once I've been driving for a while my car when it's running anywhere from 160 - 220 degrees will idle at 600rpms and sometimes it'll idle anywhere from 1000rpms - 2000rpms. What is the problem? How much will it cost to be fixed?

 

Check for vacuum leaks...they tend to cause all kinds of weird idle problems.