Eddie Carrara

The check engine light recently came on and my mechanic stated it was the 1457 EVAP code. He reset it and said wait to see if it comes back on . Well, strangely it come back on but then goes back off on its own. It usually comes on when I have about a 1/4 of a tank of gas and stays on after the tank is filled. When the tank is about 3/4 full it goes off. My mechanic stated that the 1457 is a tough code to crack as it could be any number of parts. He was also surprised to hear that the light goes off and on. Has anyone had this happen to them?