I have an 01 2500 4x4 auto and im only getting about 14-14.5 mpg on average. I have a k&n filter and a 4' exhaust kit without the resonator. Ive heard conflicting reports that something is wrong and I should be getting at least 16-18 in town and Ive also heard nothings wrong and this is all I should expect. Any ideas??? And if so, directions to head??