What have you done with your exhaust?

[FordFastiva]

Thermostat is new and works good batter than the old one. And everything else checks out except intake manifold coolant sensor

Changed the air filter on my car, every time I drive it, the MPG keeps getting better and better. I found out that the car I bought sat 6 years, hardly even rusted in the rain, sun, snow, and humidity. I was getting 19 MPG combined, now I'm getting roughly 32 combined (keep in mind, my car is a 3 spd. Auto so it's not going to get as good as the Manual does.)

[Meepersly]

It has a brand new air filter but maybe I just need to wait a little and see how it goes