Q: P1456 - Check engine minor EVAP Leak.. Not the Gas cap

If you smell gas, there can be a leak in a number of places. All the fuel lines should be carefully inspected to make sure they are secure and undamaged, all the way up to the fuel injectors themselves. Even a minor fuel leak can allow fuel to evaporate, making is seem ;like you are getting poor mileage. While it should be inspected along with all the fuel lines, if you especially smell gas inside the car, the fuel pump-to-fuel tank seal should be inspected as well. The fuel pump can be accessed under the rear seat bottom. Once it is removed, there is a triangular-shaped panel in the middle of the floor. The wiring harness grommet must be removed first, then the 3 screws can be removed to access the fuel pump, located on top of the fuel tank. The fuel line connections and tank seal should be inspected and/or replaced if needed. Other causes can be a leaking or damaged purge valve or canister, as well as hoses connected to them.

The best course of action would be to have a certified technician check the system for fuel leaks before randomly replacing parts. That can get expensive as most fuel and electronic-related parts are not returnable once purchased and/or installed.