The 2013 Nissan Sentra is fully redesigned. Highlights include a roomier interior, improved fuel efficiency and a new electronics interface. Under the hood is a new 1.8-liter engine. It's slightly smaller than last year's 2.0-liter engine, and makes less peak power (130 horsepower versus 140 hp). This may seem odd until you realize Nissan's goal was to compete with the Sentra's rivals, which advertise 40-mpg capability on the highway. Indeed, the Sentra FE earns this same impressive rating, while overall fuel economy is impressive throughout the lineup. A newly revised continuously variable transmission (CVT) comes on all but the base model. Nissan estimates that the CVT-equipped Sentra returns 30 mpg city/39 mpg highway and 34 mpg combined, making it one of the most fuel-efficient cars in its class. Source: Edmunds.com