Tank Assembly problems of the 2005 Mazda Tribute

I purchased a 2005 Mazda Tribute in July, 2005. The sticker on the car had an average mileage of 19 to 24 miles per gallon. I, to this date get 11 to 13 miles per gallon and 17-19 on the highway. I truly believe there is a problem in the fuel system or the engine. Contacted Mazda and was told epa was to blame and I needed to let the car get broken in. I currently have 6500 miles and still get 11-13 miles per gallon. I have a 16 gallon tank and get anywhere between 180 to 200 miles per tank. Dealer says nothing wrong and hasn't replaced anything.

When fueling I constantly have to over ride the pump due to the fact that pump turns off prematurely. Even though I don't believe this to be a safety hazard I do find it an inconvenience. I have also have read that this is a pretty common problem.