Gas mileage in this latest generation of CLS sedans is improved, and it no longer gets taxed for excessive consumption, but it's still at the low end of economy for bix, sexy sedans.
In base trim, the 2012 CLS 550 is rated by the EPA at 17 miles per gallon on the city cycle, and 25 mpg on the highway cycle. That's markedly better than the 2011 edition. The efficiency news is even better in versions with all-wheel drive or the magnificent AMG-tuned V-8: both the CLS 550 AWD and CLS 63 AMG are rated at 16/25 mpg.
For the AMG model, that means no more gas-guzzler tax. Still, Mercedes offers some of its exceptional BlueTEC diesels in the CLS in other markets--and we'd imagine a 30-mpg highway rating would look just as good here as it does over there.
The CLS also has a new "controlled efficiency" mode programmed into its automatic transmission. By switching into that mode, drivers can launch the CLS from a stop in second gear, and can stretch and smooth out shifts for slight increases in fuel economy. Mostly, we noticed this mode does best at eliminating some shift shock in urban driving.