ToddS

I think the obvious thing you might be missing. Stay out of the throttle. Seriously baby that thing if you want fuel economy.

Was running the scan tool the other day. Slow speed, slow acceleration was only 5 mpg. If you're accelerating with any kind of speed then your mileage is going to be horrible. It takes a lot of fuel to get a big heavy truck moving.

Putting some much lower rear gears should help too. In my old mustang going from 2.73 to 3.73 make my mileage much better. Seems 4.10s would be good in the truck since tires are taller.

CaileighMoore

I feel like a drive like a grandma with this truck. I have been trying not to step on the Ga's too much and if I'm coming to a red light basically glide a good quarter mile before. Saves gas and brakes. It is crazy going from a tiny car to a truck that's 3x the weight.

So I haven't filled my rear tank at all, it was basically empty when I got it and I planned on filling it this weekend when this tank was getting low. Well I checked it this morning and it almost has half a tank. Is this something difficult to fix on my own?

Rusty but trusty

You figured out your mileage problem your front tank is pumping fuel into your rear. Very common, you can find several threads about it. To fix this problem you would need to replace your rear fuel pump assy. My truck has always done it and I just learned to live with it. I guess its up to you on how much it bothers you.

CaileighMoore

Haha woooo! I'll look into it and read a few DIYs and see if it's something I can do. Honestly I'm just happy it's not eating up gas like I thought it was. I'm actually not getting that bad of mileage if I have an extra 9 gallons hanging out in the back I didn't know about. Haha! Yay thanks everyone, I appreciate the help!

fltdriver

If you just use the rear tank you won't even have the crossfilling problem as the bad check valve is located in the rear pump. BUT... if you do decide to replace the pump, change the tank straps too (assuming the tank is in good shape and doesn't need replaced also), they will last quite a while but any time you drop the tank they should be replaced just as a safety precaution, you wouldn't want to bend one removing the tank (creating a weak point) then have it fail while your driving down the road and drop a full tank of gas on the concrete doing xxMPH, basically it would be a bomb sliding down the road throwing up sparks just begging to go off.

Now that the oh no stuff is out of the way...
For anyone else that experiences significant MPG drop (and they aren't cross-filling) one of the first things to check would be your vacuum lines, the small ones coming from the manifold tree, a crack in those will cost you an easy 3-6mpg.

Also pull codes to see if you have an o2 issue.

These don't apply to you ms. caileigh but they may to someone else, glad you figured out your problem so quickly.