The Mazda3's gas mileage used to be one of the most disappointing aspects, but that's all changed; mileage-minded shoppers for 2012 can now choose either the Mazda3i Touring or Grand Touring models (hatch or sedan) and get much improved fuel economy, with up to 40 mpg on the highway, thanks to an all-new generation of Skyactiv powertrains.
The new, high-compression, direct-injection 2.0-liter Skyactiv engine has dramatic reductions in mechanical, pumping, and thermodynamic losses, and Mazda has redesigned all the ancillaries (like water and oil pumps) to make the most of it. Both the six-speed automatic and six-speed manual transmissions that come with that engine are all-new, too, with the automatic boasting much-increased torque-converter lockup--helping mileage and also increasing the level of control.
EPA fuel economy ratings for the rest of the line aren't nearly as impressive. If you go for one of the base 3i SV or Sport models, or one of the Mazda3s models, you'll get the carryover engine and transmission combinations, with ratings that range down to 21 mpg city, 29 highway.
Although we can't yet estimate what you'll see in real-world driving, Mazda says that its 40 mpg will be better than others' 40 mpg. And in an early fast, aggressive drive, up in the mountains, we already saw better (about 30 mpg) than we'd last seen in a weeklong test (25 mpg) of a Mazda3s automatic.