Very bad gas mileage approx 12mpg

Howdy, first off obviously I'm driving a taco, bad gas mileage is a part of that. However, my gas mileage on my 2014 sr has decreased from about 17mpg to about 12mpg in just about 2 months. I took it into a Toyota shop and they tested the engine and said everything looked fine. Does anyone have any thoughts? Much appreciated. Thanks

 

Gradual drop or sudden? What have you changed ... lifts, tires, throttle control, bed racks, OTT tune, the way you accelerate or brake, engine maintenance that may have dislodged any of a million connections ... anything you can think of will help?

 

How many miles on the truck? When’s the last time spark plugs changed? What size tires and when were they installed? Have you cleaned the MAF? If not then do so. Any added changes or mods since you were getting 17mpg? Doing more city, stop/go driving?

 

Check brakes for dragging calipers

 

When did it drop? Around the same time fuel stations changed to the winter blend fuel?

I mean 10-12mpg is roughly what I get all the time, but I tend to hold gears and make my time more enjoyable in the truck...