The 2011 Volvo C70 is fitted only with a five-speed automatic transmission paired to its 2.5-liter five-cylinder engine. A six-speed manual gearbox offered in previous model years is no longer available (although, confusingly, the EPA still has mileage ratings for that combination on its website).
The EPA rates the 2011 C70 at 19 mpg city, 28 mpg highway, for a combined rating of 23 mpg. That's something of an improvement over its mileage numbers in earlier model years, but it's still pretty low for what’s essentially a two-seat car with occasional seats in the back. Any number of four-door compact sedans offer far higher mileage ratings.
But no one who’s considering a coupe with a retractable hardtop for open-air motoring is likely to be cross-shopping the Volvo C70 against, say, a 2011 Hyundai Elantra, with its 40-mpg highway rating. For buyers deciding whether to treat themselves to the C70 convertible coupe, gas mileage is likely to be one of the least important factors.