My 98 Jetta Tdi has been getting horrible fuel economy in the city lately. I drive fairly respectivily but like to put my foot into it every now and than but can't get more than 400km of strickly city driving. To school and back pretty much. On the highy way i can get around 900km, to a tank. Is something with my car? i know it is winter and fuel economy goes down but even in early november it was this bad also. what can i do to fix it? Thanks