While it's far from class-leading, gas mileage in the Lexus GS isn't at the bottom of the pack. When it updated the sedan in 2013, Lexus carried over the GS' base drivetrain and its six-speed automatic, while other luxury brands have updated their offerings to include seven- and even eight-speed automatics. (An eight-speed automatic is due on the rear-drive GS sometime in 2014.)
The EPA rates the GS 350 at 19 miles per gallon city, 29 mpg highway, and 23 mpg combined. Lexus says that's a 2-mpg improvement over the prior generation.
For comparison, the seven-speed Infiniti Q70 is rated lower than the Lexus GS 350 at 18/26 mpg, while the Mercedes-Benz E350 is much higher, at 20/30 mpg, and the eight-speed Hyundai Genesis sedan is pegged at 19/29 mpg.
When it's outfitted with heavy all-wheel-drive gear, the GS 350 is downrated to 19/26 mpg, or 21 mpg combined.
The best fuel-economy ratings of the Lexus GS lineup are reserved for the GS 450h hybrid. It's scored at 29 mpg city, 34 mpg highway, and 31 mpg combined.