Can I go back to the seller for poor fuel economy?

Hi Finian,

Possibly, but it depends entirely on the car and how you're driving it. If you're talking about a small diesel-engined hatchback, then yes, there's quite possibly a problem if you're only getting 19mpg on average. Even driven for only short hops around town, most would manage at least 35mpg on average. Certainly worth a visit to the dealer to at least have it looked at.

That said, the single biggest influence on fuel consumption is driving style. Have you changed the way you drive, or your regular route lately? Are you spending a lot of time idling at traffic lights where you previously weren't? It all adds up...