Gas Mileage Issues

I'm no gear-head, but I'm told that re-gearing the axles will restore SOME of the vehicle's performance.

 

Dam. I can't even fathom this. More than a 100% increase over mine. V6? All highway? No ethanol? Vsc off?

 

I have a 2013 V6 2WD Crew-Cab 5'bed with Firestone Destination AT Stock tires/wheels. 86K on the odometer, have been averaging 21-22.5 consistently, even in the Texas wind/heat but recently 19-20 MPG is the norm. So, I washed my K&N aftermarket filter and am considering hotter plugs. However, an old guy at a local gas station told me "Winter Fuel" has a lower volumetric efficiency (lower flash point, easier cold starts) than summer, hence lower MPG. ???? Great theory, but I've never heard of climate driven (so to speak) fuel variations. Anybody else?
I'll try my usual techniques of slightly over-inflating the tires, hotter plugs, non-ethanol gas (available here) and maybe slowing down... Maybe
Smokey

 

I’ve heard it both ways. My mileage goes down when it’s cold because my engine works harder warming itself up. Fuelly has proven it because I have a statistical record. Technically cold gas has MORE energy than warm gas, but I don’t know how that equates to atomization efficiency in the fuel injector.

 

Yes. It's lifted.