8 to 11 MPG on 2007 Chrysler Town & Country

I get about 165 to 210 miles per 20gal tank of gas. The MPG "computer" in the overhead lists as low as 1.8mpg when at idle at a stoplight. I can increase the mileage by constantly re-setting the MPG computer, although the dealership says thats not possible. Dealership mechanics are lazy, incompetent, or both. They refuse to find, let alone fix the problem. Their standard answer is, "Well, the computer does not indicate a problem." Apparently cars could not be worked on until computers came along.

Asked by for the 2007 Chrysler Town & Country