in the city, im lucky to get 12, on the highway i actually get around 17. i have 3.55 gearing with 30" tires, 4.6 auto. usually drive 75mph on highway (guessing thats about right, 120 km/h)

i have the bosch platinum plugs (makes no difference) and a k&n air filter...

 

chevy trucks wit the 5.3 get about 14.5 normal... between high way and city.. i mean would a programer help???

 

2002 5.4 stock suspension getting 12-13.5 in town and 14-16 highway. similar to the other posts.

 

I've got a 97 4.6auto 4X4 135k K&N filter, 265/75/16 tires at 35PSI, no muffler, and still only get 12 combined highway and city. 40%high 60%city. Something doesnt seem right. and what is the GOTTS MOD?

 

2008 s-cab 4.6 auto with 33x1250 17's flow master 40 muffler to duals, k&n drop in, gotts mod and edge evolution. i average 11-12 in town and 14-15 highway. with the edge set to trans only. sucks when i had stock tires and the same mods i averaged 14 in town and 17 on the highway. drove 1226 miles on 3 full tanks of gas right before i got the 33's

 

These MPG are only dreams to me.

I usually aveage 4-6 mpg highway or city, maybe 7 on the interstate if I'm lucky

4.6 4x4 auto, Dana60 front and rear 5.38 gears locked. with 49" irocks.

The MPH were completely on, as well as RPM's it felt stock, just huge.

Going 85 gave me a 1/1 ratio though, It drank the gas, you could actually watch the needle drop. I ran out of motor at 88mph

Before going built, I averaged 10-12mpg. With 3.55 gears and tires ranging from 33-37's, and would motor out around 115-120.

Theres my HORROR story

 

That might be backwards - if you upsized your tires, your speedo should say 73, and your GPS should say 85. But you do bring up a really good point rompn4x - if you have swapped out your wheels and tires to larger than stock sizes, your fuel economy will be "worse" but not really, let me explain...

I'm going to use random numbers here just for the sake of explanation, so don't flame me if I'm off a little from what is reality. Let's say your F150 came from the factory with 16" wheels, and tires that had 5" sidewalls, for an overall diameter of 26". This means the circumference of your factory tires is 81.6" - this means that every time your tire travels one full revolution, roughly 82" of lateral distatance is covered. This is what your speedometer and odometer use to determine MPH and distance travelled.

Now lets say you swapped out your factory tires for 31's. The circumference of your tires is now 97.3", almost 16" of lateral distance is covered for every revolution. If you do not calibrate your speedo or odometer, your truck still thinks it is only traveling 81.6", when in fact it is travelling 97.3". So when you say you are only getting 10 or 12 mpg because you swapped out your tires, remember, you can't use your odometer as a scale if you did not calibrate it to match the new tire size.

Being an engineer by trade, I pay attention to stuff like this. I document all my fuel stops and factor economy on the spot, always have. When I had factory wheels and tires on the truck, I saw 17 MPG for highway, 12 for city, and 15 for blended driving. Once I put new wheels and tires on, I was excited to see the difference. Using my GPS (which I did use to calculate the before state), I saw that I still got 17 MPG for highway, 11 for city, and 14 for blended - my fuel economy did not change nearly as much as I would have expected, but it makes perfect sense. The larger tires are heavier, and require more energy to speed up, so my city MPG dropped. The tires are also larger, which means my engine turns lower revs on the highway, so my highway still looks great.

I used my odometer a few times just to see what the difference was, and it said I was getting 14 highway, 9 city, and 11 blended. So my fuel economy did drop, but not really.

 

Naw the only horror story for your truck is not seeing the Honda in front of you. Eat em up.

 

Ha, If you only knew, don't want to hijack though.

But I will say this Ferry, Galveston!