I hope I am posting this in the right place. I have a 2006 2500 4WD. The truck has and upgraded trans with a three disk converter, wilson intake manifold, AFE CAI, Superchips flashpad. I recently installed a 5in turbo back exhaust from FTE with a resonator, high tech turbo stainless steel exhaust manifold, Fass 150 and put new 265/75/17 Michellin LRR tires on the truck. Now my mileage has gone to . I have checked every thing I installed to make sure there are no leaks of any kind. I just towed my Jeep on a trailer to Sliverlake and I only got 13.85 hand calculated. I was getting better then that without the mods I just did. It just seems like the truck is just drinking the fuel. I also tow a trailer in town with my mowers and that mileage towing that trailer is . The truck has just turn 60,000. I did all the new mods to help my mileage not make it worst. Thanks for any input you guys can give me.