I drive a 2005 Chrysler 300C and get over 30 mpg highway. I was looking at a new 2012 300 and the sicker claimed only 25 mpg. Same engine, same accessories etc.
That’s how it is now. Rather than increase the CAFE requirements(which would make people angry and requires government action) they did the back door method by having the EPA change the parameters of their fuel mileage tests. Cars have more horsepower nowdays and if you use that HP stupidly, your mileage goes down real fast. In other words, your mileage varies more depending on how you drive. That makes it easier for the EPA to get the mileage results they want to get by adjusting the parameters of the test.
That 25 mpg hwy is actually the same as the sticker in 2005 ,, EPA shows that 2007 and earlier years mileage estimates do not compare directly ,, looks like a calculation change rather than a test change .. http://www.fueleconomy.gov/feg/Find.do?action=sbs&id=20966 click on “view original EPA mileage” about mid page.