Not sure if '10 has the dash info center. It would show the mileage to empty.

Do you have unusual tire wear?

 

Oh ya, that's what you're talking about. Yes I do have that, but have found it to be pretty unreliable when telling me my average MPG and miles to empty.

 

As for the tires, no. I just had them rotated and realigned after I put on the level kit. No funky wear or anything. And all my psi's are good as well.

 

winter blend fuel plus the level. around 2mpg for the level and 3-4 on avg with winter blend fuel.

 

Carcrazy, thank you very much for reassuring me! See, I figured the level kit wouldn't cause a 5 MPG drop on its own. My fiance is an astrophysicist and the physics/aerodynamics of it didn't add up. Wow, and I didn't realize about this winter blend stuff until recently. And I sure didn't realize how much it lowered fuel efficiency! Thanks to everyone who responded as well!

 

Winter blend is easily responsible to the largest chunk of your mileage loss.
Sure your front end coming up a little bit has an effect on mileage, but unless you jacked the thing up a foot, and have 44" tires blocking the air on either side, the change will be negligible.
As far as your 31s are concerned, I wouldn't worry about 'em. I can't imagine your stock tires being that much smaller, but either way, 31" tires just don't weigh enough and don't have a big enough footprint to make your motor have to work much harder to push 'em.
Hopefully the winter-blend starts getting replaced later in the month, or March at the latest.

 

I say its 50% the level kit and 50% winter blend gas. The level kit changed the aerodynamics of the truck and I always lose 1-2 mpg's in the winter due to the winter blend gas.

 

Surferguy001? Its a pickup truck with a bed,, its heavy, it takes a lot of engine power just to pull the weight of the truck around, with a load or towing thats even more weight. You need a pickup truck, try hauling a load or drywall with a Prius. All the pickups out there get about the same mileage, even the mini pickups don't do much better. I understand the price of gas is going up and everybody is paying more attention with their gas mileage,,, but you need a truck for hauling and towing and what are you going to do?
Everybody else that owns a pickup is in the same boat as you,,, look at me my mini V6 Tacoma is only getting 15 MPG and I can't haul or tow not even half of what you can.
Look at the guys that paid big money for the eco-boost thinking it would get 21 MPG and later found out it only gets 15 MPG,,, they don't like to talk about that.