[AKElroy]

I know this thread is probably overdone, but I am curious regarding my recent mods KILLING my mileage. I recently mounted 305/65/18 AT KO's on the stock rims, replacing the stock 275/65/18's. I also installed the ReadiLift 3" front / 1" rear level kit. Mileage has tumbled from 13.5 / 14.5 to 10.8. Even correcting for the larger tires, I am getting a true 11.4 MPG. My driving style has not changed. I keep 40lbs all around, and this has the new AT's slighty domed (they are mounted on stock rims .5" narrower than recommended) so I do not want to go with higher PSI lest they center-wear prematurly. Is it possible the fuel / shift mapping is incorrect for these larger tires? Do I need to do a computer reset? If so, should I tie the cables together? Am I missing something else? The only other mod to the truck is the charcoal delete when I first purchased it. Need help--I actually need the lift & tires for a recent deer lease acquisition that is similar to driving on Mars. 2007 Crewmax 5.7 4X4.