Volkswagen Jetta fuel economy varies depending on the year of the vehicle and the type of engine it has in it. The gasoline burning engines from 2004 got 22 city miles per gallon (MPG) and 29 highway MPG. The new 2011 models get slightly better mileage at 23 mpg city and 34 mpg highway. For the best fuel economy available in the Jetta line of vehicles, one would have to select Volkswagen’s diesel engine. The diesel engine Jetta from 2006 produced 36 mpg city and 41 mpg highway. Unfortunately, the 2011 diesel only gets 30 mpg city and 42 mpg highway.