i got an 05 STX with the 4.6L. V-8 and i think the best way to get better gas milage is to #1 stop lead footing it. #2 exhaust system and performance air filter ( i got the fram air hog, but K&N is the best i think.) #3 check tire pressure. #4 lighten your load, if to got stuff in the bed, get rid of it. #5 fuel treatment cleaner, you can find it at any part house. and if that doesn't work. then trade it in and buy a honda.

 

treefarmer -- we had a Santa Fe 2.6 I think V-6. That was a thristy little SUV
for its size

 

I figured I'd throw my 2 cents in on what I saw on my new 06' XLT on it's first long trip. My truck is an 06' XLT extended cab 8' bed, with the standard 5.4 auto, but with also the standard 4.10 ring gear (8' bed option). All I've done to this truck is transfer the tonneau cover that was on my F250 over to it and swap out the ugly painted HEAVY wheels for a set of Eagle aluminum ones.
On my first trip north with the truck two weeks ago I topped off the tank right near my house. There were two of us in the cab, a backseat full of hunting gear, and a bed full of plywood parts to a big shipping box we were going to make into a hunting blind, all under the tonneau.
I kept the speed to about 68mph, with the occasional trip to 70 to pass. The ride from Dearborn Hts. to Port Huron is approx. 75 miles, all highway. When we stopped in Port Huron I decided to re-top the tank. The truck only took 3.8 gallons. 75/3.8=19.73 MPG!!! The truck only had 417 miles on the odometer. I couldn't believe it. The best I ever got with my 04' F250 FX4 on that same run with no tonneau, and no tailgate on the truck was 16.3MPG, and I kept it under 65MPH all the way.
The gearing with these trucks seems to do wonders. Even though my Superduty had the two valve 5.4, it also only had 3.73 gears, and an unfortunate 1000 lbs weight handicap.
All in all, when this motor breaks in it should get better. I can only hope.

 

Hi xc600,
I think getting a mileage reading after only 75miles is a little premature. Considering variability in where the gas filler decides when the tank is 'full' and shuts off, your mileage calculation will most likely vary quite a bit. That's of course you're not topping off the tank by watching gas fill to the brim :-)

I've been getting 15mpg around town and bested a tad under 17mpg on 100% freeway driving at 65-70 and occasionally 75mph in my '05 FX4. That's bone stock and with no tonneau cover and not hauling much more than about 400lbs of people not including myself and stuff. My mpg has been fairly consistent 15mpg every fillup over 9K miles so far for the majority of my driving which consists mostly stop-and-go expressway driving and average 30mph freeway speeds .

 

well it made mine go up 1 mpg tested on a 90 mile trip 45 miles each way the weather was the same one day went there and back with the cover rolled up and the next day with the cover one. plus it is really nice you go on trips

 

I drove a E150 inline 6 from Michigan to Mexico City to southern Mexico and back. I only purchased the van on the promise from the dealer that the 6-cylinder would make it up the mountains in Mexico. Would you believe the darn thing never downshifted.....Now, it only liked to cruise 70mph to 75mph or it burned some oil... I just bought a f150 with the 4.2L which has aprox. 50 more hp and the same torque as the E150 and I have no complaints. I know you must have to hold onto the steering wheel when you step on a 5.4, but my 4.2 gets on the freeway at speed without any difficulty. I got the smaller engine because I do not have a need to tow more than 5000 lbs, it is less weight on the front suspension leading to a longer suspension life, he truck handles better with less weight on it andthe payload for the truck increases over the larger engine because it weighs less....As long as I do not have a lead foot, I get 15mpg city and about 22mpg highway with 300 pounds of sandbags in the back-----yes I live in the north.

 

I dont care what any expert says, I get better mileage with my tonneau cover installed. It has proven the same on every truck Ive ever owned. As for upgrades, a catback swap is always nice. You can skip the filter upgrade, since the OEM provides enough flow, and superior filtration. The mod that provides the most power increase (as well as mpg boost for me) is a tuner. I had a Superchips on my 04, and I gained 1.5mpg. I cannot say you will gain the same, but it sure worked for me.

 

Ditto on that.

Tonneau's have always helped out the mpg dept for me. You can see why if you understand the areodynamics of our trucks, and what an open tailgate actually does to airflow.

I did try a tuner, Diablo to be exact. After several Diablo tuners over different trucks, this past one really left a sour taste in my mouth.

Right now I average 15-18 on the open road at 70mph all winter driving. 20 mpg would be nice, but I'm not exactly excited about a tuner for this truck after the last tuner episode.

Maybe I'll try the SCMT.

 

[QUOTE=aquaman]Hi xc600,
I think getting a mileage reading after only 75miles is a little premature. Considering variability in where the gas filler decides when the tank is 'full' and shuts off, your mileage calculation will most likely vary quite a bit. That's of course you're not topping off the tank by watching gas fill to the brim :-)"

Actually, I'm very careful about where I fill my truck to. I work for Ford's biggest supplier, and I've witnessed more than one "fuel fill" test in our garage before. Believe it or not that's one of the things we're required to test to, initial shutoff during fill. When I check mileage though I DO fill it to the point where I can see the fuel in the filler neck. That way, especially on the run from Dearborn to Port Huron, I get accurate numbers. It's just the test technician in me I guess. I'm still convienced that gearing on this truck is everything though.

 

I purchased an UNDERCOVER tonnerau cover, I'd make a couple of changes to it, but over all I like it. As for gas mileage, my 05 screw picked up 10%+, both in town and hwy.

 

If you buy all these add-ons to increase your overall mileage, how much will you spend to gain so little? And after purchasing these things, how long are you going to drive it? After all, the increase in mileage compared to the amount you spend you will more than likely have to drive your truck many, many YEARS to break even, let alone pay for it! If you add these things for fun, or simply because you want to is fine. But, if only to gain a small amount of fuel mileage to me is silly. You bought a truck, did you really buy it for fuel economy or, did you want a truck? Otherwise, buy a small compact for mileage!

 

If I could by something that keeps my items dry or at least less visible inaddition to helping out the MPG dept, why in the world would it be a bad thing?

The same can be said about tuners.

I do agree that there is a point in that buying an mod for the sole purpose of MPG is a tad bit reaching, tornadoes and other whiz-bang mods come to mind.

 

I did say, if you bought these things for fun, or simply because you want to is fine with me. My point is simply, if only for fuel mileage the cost of the products, usually is more than your return in fuel mileage unless you plan on driving the vehicle for a very long time. The few cents you save in fuel, compared to the cost of the product, you wont get your money back.

 

Here Here!! It's same exact thing that can be said about those who trade in their new SUV's for a hybrid so they can save a few bux at the pump. Ooops... I don't think we want to go there and start that discussion... :-)

Also think about all the decorations that people put on their vehicles such as name-brand ski racks during the summer, brush guards that look like they're good for battering rams, fog light rails, etc. Not only do they add unnecessary weight to the vehicle, but they also increase aerodynamic drag. Both affect mpg adversely.

 

Just officially came back to the site and thoght I could contribute to this thread with my own experience.

The Ford owners manual recommends the use of a bedcover for increased mpg.

My intake mod and exhause mod did little to increase mpg.

The most notible change was the purchase of a tuner. Better throttle response all the way around, even on tow tune. If you can keep you foot out of it, you can easily get another 1-2 mpg.

Other than that, keeping the air pressure up and go light on the throttle.

Good luck.