i have a 1998 exp. 4x4 and I got right at 520 miles on a tank while traveling. this is with cheveron premium i'm quite suprised and happy. anyone else?? oh yeah it has the 4.6 liter in it. this is without driving in 4 wheel drive of course. also when i switch to synthtic engine ooil and treansmission fluid i'm sure it will probably eek out a tad bit more mileage.

 

Have you performed any modifications to your truck or are you still running the original factory setup? Please let us know what you did for your improvements in your MPH.

 

Man, that's really good! The most I have been able to squeeze out is close to 400 miles which = ~16MPG, but that is not on a road-trip. I also have the 4.6l, with a K&N Intake and Magnaflow cat-back. I usually fill up with 25 gallons. I have tried lowering my speed by about 10mph over this last tank and I am already to 340 with still over a 1/4 tank left, so I should be seeing the results of a lighter foot. I will be making a trip from Cali to Texas in October and I would be more than happy to see 500 miles per tank!

 

is it true that performance modifications. exhaust, intake throttle body. give you better mpg. or just under normal driving conditions. i would think that if these things did give you more mpg, wouldnt ford have had taken advantage of it?

 

Most I have ever seen out of mine was 436. All hiway. Was pretty happy with that carrying 4 adults 2 kids and luggage.

 

Well, that is the big question! I think they would do that if it was cost effective to them (and are making impovements every year). But remember, they also have to mass produce these items and meet the emmisions requirements and NVH levels set to satisfy every customer, including my Grandma. It is a lot cheaper to bust out thousands of molded plastic intakes and smallish basic metal exhaust systems than it is to make polished aluminum intakes and stainless, mandrel bent exhausts. They could do it but the final cost of the vehicles would be higher, they would sell less and lose money on both ends. I think if someone was disciplined enough and had the time and resourses, they could prove that an intake and exhaust will give better MPG results over a long-term test. The problem is when most people add these mods, they tend to rev a little more, go WOT getting on the freeway just to hear these mods in action, start it up and rev it for no other reason than to show off for your friend that is doing the same crap to his Chevy, etc etc. So your mileage may be the same or worse, but not because the mods aren't working, because we are running the truck a little harder than before. I will be the first to admit that when I first got the truck (it already had the cat-back and I soon swapped out some no-name intake for the K&N) I liked to hear and feel the power. But I have learned over the past several weeks, now that gas is skyrocketing, to feather the gas pedal, coast whenever possible and just cruise around instead of tearing around like I was still in my Focus. And my gas milage has increased dramatically since then. I can tell over the course of a tank of gas that the few times I get on it when I have "company" in the truck or I'm late to work or whatever, my gas mileage suffers. I firmly believe that all things being equal, meaning driving style/habits, road condition, weather, routine, etc, a modded truck will get better mileage than a stock truck. I would remove my intake a do a test, but I don't have the discipline to conduct an appropiate test.

 

no mods at all except b & & auto trans in the transfer case. other than that. nothing. also it seems to me that i get better gas mileage out of chevron than any other fuel. i get the worst gas mileage on every vehicle we've owned with shell v-power. exxon is better but it seems chevron premium is just way better in terms of gas mileage. in my 02 gt mustang i can't get 300 miles on a tank unless i use chevron premium when i use shell I always only get about 240 miles on a tank with exxon it was 260 miles. mind you guys i squeeze every bit of fuel i can in the tank. i even rock the truck and car a bit to burp the gas tank to get as much gas as posssible in the tank.......lol

 

How many gallons would you say your putting in your gas tank after the gas pump stops pumping, and the nozzle clicks off on its and you rock your truck? I think thats the reason you attained 500 miles on a single tank.

 

Also at what speed were you maintaining while on the highway? I notice I get better gas mileage as long as I maintain the speed at 60MPH. Generally as long as the RPM's is not over 2000 it gets decent gas mileage.

 

Yeah, that could have something to do with it. I know that the most I have ever put in my tank was 25 gallons, and that was when I thought I would not make it to the next gas station. So, I still had 3 gallons in there. I base all my MPG calculations on 25 gallons because that is all I can get in there. That last 3 gallons could be nearly 60 miles on a road trip.

 

according to my gauges, Im only getting about 317 a tank and this was after I switched to K&N filter and started using the cheapest gas I saw.

When I bought the pig, it was getting 340/tank. I changed the oil and jumped up to 375/tank. Changed the filter and blammmmm......it fell. I might switch back to the old filter at the next oil change and see what it does.

 

I just got home from a 6200 mile driving vacation, and averaged just over 16 mpg, with my highway driving averaging around 75 mph. MY BEST mileage was while in Wyoming, running their ethanol enhanced 88 octane mid-grade,(their regular is 85 octane) and even up/down hills in/around Yellowstone, I still got over 18 mpg. My worst was from a tank of crappy gas in Nebraska, and it cut me to about 15 till I finally got it all driven out/diluted. All in all, the truck drove nicely, and handled well, and I'm happy with the mileage, just NOT with the current gas prices!
By the way, to find the lowest gas prices in YOUR area, be sure to check:
http://www.gasbuddy.com/

Sorry forgot to add...2005 Expedition King Ranch 4X4, 5.4l automatic. NO aftermarket goodies...yet.

 

Your speed of 75 mph isn't exactly conducive to getting the best fuel economy. I've got a '97 EB Expy with a K&N replacement filter. On the highway, with cruise control set at 60 mph, I get 18-19 mpg. That's also running with 60 psi in my BFG Rugged Trail radials & synthetic blend motor oil.

 

wouldn't one's most efficient speed be contingent on one's gearing?

 

Good point. Absolutely correct.