Check engine light on and check fuel cap?

My check engine light came on I took it to AutoZone they said it was an evap leak next the check fuel cap light comes on I replace the gas cap reset the codes by unhooking the battery. Well, a week later the check engine light is back on 3 days later the check gas cap light back on. It drives good gets good gas mileage I don't smell any gas at tank I checked the gas tank clamps there tight I don't know what else to check next.