long story short ive tried many ways to squeeze aver mpg out of my jimmy as possible. best i get city is 15. most of my everyday driving is stop and go with the very occasional dash to 55 or 60. it has factory 3:73 gears in it. dose it make sense to put talle gears in such as 4:11's or 4:56's? it wont have to work so hard off the line as these trucks are so underpowered. the rear is simple enough. my question is what was the talles gear set factory offered in the trucks.i want to change gears and have the pcm flashed so shift points and everything stays correct. were do i find gears for the front? how big can i go?