With A4 sedans toting four-cylinders and the S4 sporting a six, gas mileage numbers are understandably varied across the lineup. The differences aren't as broad as they could be, though, since the more powerful models have opted into smaller engines with supercharging, instead of the V-8s that used to power them.
The A4 sedan is offered with a choice of three transmissions, and either front- or all-wheel drive. In base form, the front-drive, CVT-equipped A4 is rated at 24 miles per gallon city, 31 miles per gallon highway, for a 26-mpg combined rating. Adding quattro all-wheel drive to that version drops gas mileage to 20/30 mpg, or 24 mpg combined.
The manual-transmission A4 is offered only with quattro; it's rated at 22/32 mpg, or 26 mpg combined. And our preferred version, the A4 with the eight-speed automatic, gets an EPA-rated 24/31 mpg, or 26 mpg combined. That means the CVT's only advantage is in price; if you can afford it, by all means, go with the pricier, nicer automatic versions.
As for the S4, it's been powered by a 333-hp supercharged V-6 since the 2010 model year. With a choice of either a dual-clutch seven-speed or a six-speed manual, both versions come with all-wheel drive. With the dual-clutch, the S4 earns an EPA-rated 18/28 mpg, or 21 mpg combined; with the manual, it's the lowest of the range, at 17/26 mpg, or 20 combined.
While the related Q5 crossover gets a Hybrid version in the 2013 model year, none is planned for the A4 sedan. An A4 diesel has been rumored for years, but as of yet, it hasn't materialized for U.S. customers.