MPG with larger tires and lift questions

You should be happy to have such good MPG, as most others have said, that is an aerodynamic nightmare; however, aero plays less into effect at low speeds. In your city driving conditions, you're fighting rolling resistance with a 20% wider tire (might consider something closer to 10" next) and about 20% more weight it takes a lot more power to keep it in motion. Also, those big rims have a lot or inertia which means a lot of fuel is being spent to get them moving.

 

Normal. Clean your air filter. Drive smarter. Reduce weight. You might get 14.