The 2013 Acura TSX remains positioned somewhere between entry luxury sedan and more of a sport sedan; and in either role, it's reasonably green--although the field is changing fast and even this year there are better options.
The Environmental Protection Agency (EPA) rates the TSX Wagon at 22 mpg in the city and 30 mpg on the highway; the sedan earns ratings of 21/29 mpg for the four-cylinder manual, while the automatic boasts 21/31 mpg. There isn't all that much of a penalty for the V-6; it's still rated at 22/30 mpg--which is impressive considering it has 79 hp more.
Over quite a few drives of the four-cylinder models, we've had no problem seeing somewhat better than those EPA numbers--especially with the manual transmission. But with the introduction of new four-cylinder models of the BMW 3-Series, earning up to 34 mpg highway, there are now some markedly better fuel-stingy choices on the market.
Acura offers no hybrid version of the TSX, although there is a hybrid version of the smaller (and new for 2013) ILX.