So being new to this jeep thing, im gonna throw this out there because my jku is my DD. 2012 jkus w 3.21. I went from my jeep saying i was getting 18ish mpg avg, to now 12-13 mpg avg. I did a 2.5" coil lift and put 295/70r17 mxts on factory wheels with spacers. I havent recalibrated anything yet...