can anything be done to better the fuel milage on my 3rd gen?

you don't get 20's and mud tires to worry about your mpg. if you really care then go back to 18's and get some street tires. You will probably get 4-5mpg better.

Best I ever did on the 2V was 17mpg and that was on old plugs and tires on a really really long road trip.

At the expense of a little MPG, I would not run 5w20. My 5.4L used at least a quart of oil between changes and had a slight tick before I switched to 5w40 (yes 40) Rotella T6. Nice and quiet, runs smoother and still fires right up in 20 degree weather.

Best things you can do for these huge trucks is free up the exhaust (not cheap), electric fan, make sure all your accessories spin freely (no boogered idlers or whatever), tires are right on the edge of being overinflated, alignment is good at all 4 corners and you are up on all the routine maintenance. Even then you will be lucky to see 18mpg on the highway. Just part of the territory. Not like my buddy's 07 GMC full size pickup that gets 24mpg on the highway with that cylinder shutoff motor... grumble...

Thanks for all of the help folks. Asking for a few extra mpgs never hurt anyone. Mud tires will never give anyone good gas milage. I always say it to others, you have to pay to play and i for sure like to play.

At least gas is on sale!
I'm going to try 18" x 7.5" 2013 Ford OEM wheels to see if they make a mileage difference (OEM Expy is 18" x 8.5"). I picked them up super cheap on CL.

My theory is less rotating mass, but I don't expect huge gains.

First SUV this big, but I've had Ford F150 (2009). Installed my HOD system on it. It was getting low to mid 20's on highway and high teens on mix driving. As soon as the temp warms up, I am installing the same system on the beast..

Don't have the truck anymore, went diesel. HOD is great on diesel.

I have a edge Evo ht from my 3rd Gen I trade in... and now have eb 3.5

Not sure what to do with it...mm

Just did a 150mile one way trip and on the way there I was at 20-21MPG on the highway and dipped to 18mpg over all with about 40% highway and 60% city type driving. Ultimately I get 14-15 in pure city driving in my 2008 with only a airraid synthetic drop in and 2011 f150 snorkel upgrade.

This is pretty typical for my truck with or without a load (normal size) and to be quite honest for a 6000lbs truck its not bad. For the first 50miles I saw 21-22 but ultimately it will always settle to a best of 21 from my experience. But you should aim for 15mpg stock and honestly 12-13 with 20s and MT tires you should be happy with 12. I am seriously debating getting the tires I want due to being heavier and larger and the negative effect they will have...