I'm new to the F150, and was wondering if 14 MPG is "Normal"
Also, my message center always has 14.0 mpg whether I'm driving in the city, or on the open highway.

 

With a 32" LT tire, 14 mpg is probably normal. Though, I'd expect you'd see slightly better results on the highway, or slightly worse around town.

Try dividing the miles driven by gallons used for a couple tanks and you'll find out your average.

I have a 2wd, regular cab, manual transmission with 30.5" tires. I average 17 city and 20 highway. So considering yours is heavier, 4wd and has larger, heavier tires, your figures should be close to what you're currently seeing.

 

Just my personal experience with stock tires and my edge with my fx4 07 Scab flareside I pulled 19 mpg all highway. Now I'm lucky to get 16-17 highway with my 33s and aftermarket wheels.
I was getting 13-14 with mostly 90% in town driving with the new wheels and tires too.

 

I have dreams where I see the image of 14 mpg on my dash display...but alas...it says 10.8...

If I visit Reno, Fill up and reset the computer I can see 18 on my trip back to the Sacramento area...but it's all downhill...6k' drop over 160 miles...

 

I got a Gryphon programmer, all stock engine I get 22-23 on the highway if I'm really easy on her and about 14-15 in town.