Rogue Leader

So about 4 months ago my SES light comes on, and i re-set it, it was recurring... P1416 AIR system bank 2. I knew it was probably the AIR check valve. Obviously too damn cold to change I just lived with it. It was on up until about 3 days ago it shuts off suddenly... and hasnt come back (I actually shut the car off and turned on the ignition when it happened to make sure the bulb didnt burn out). And my gas mileage has suddenly gone up!!!

Dont you like it when your car fixes itself????? anyone have any clue what could have happened?????