The most probable cause is usually the gas cap. I'd say, try to make sure the gas cap is tight (and that the cord is not stuck below the cap). Then reset the code and see if it comes up again. You can reset the code in two ways: unplug the battery for 20 minutes or go to an autozone, loan the code reader and use it to reset the code.
I had this code come up once, it was the gas cap in my case.
If you have the surging revs, then the cause could be different. Once reason for surging rev is an air leak e.g. at the EGR or the air intake. Do you hear any sound when you are accelerating such as the sound you get when you hold a card in the spokes of a bike?