I have a new '01 150 extended cab with a 5.4L w/3..55 LS gears and I am getting 15 around town and 17.5 on the highway running 70 to 80 mph on 87 Exxon.

 

2000 5.4L 4x4 Expedition: Mostly ~10 mpg around town and up to, but never over, 14.5 on flat open highway (@ 75 mph).

 

Banshee
You are mistaken somewhere. either it is not a '98 or it is not a crew cab. Ford did not make an F-150 crew cab in 1998.
You either have an F250 crewcab(which explains your mileage), or your truck is a newer year model SuperCrew, or else your are calling the SuperCab a crew cab. Either way....sorry you are getting such crappy mileage! And here I was feeling bad about MY mileage!

 

i started off getting on average 11.9 MPG in my Navigator.
I just changed the oil and used Valvoline SynPower Full Synthetic 5W-30 and put in a K&N airfilter and I am know averaging 13.3 MPG.

Its all on that overhead computer so i know that either the oil or the filter as improved my gas mileage.

 

I GET 13.4 CITY AND 17.8 HWY. This on a 99 super cab 5.4 with 3.73 gears and a K&N filter.

 

I have checked this time and time again. There is no problem with the truck, plugs are great, exhaust if like new, intake is spotless, MAF is perfect. All I get is 10.8-11.2mpg 87 Octane and no loads. I am going to try the computer reset, hope it don't go the other way!!!

 

14.5 weekdays; 16.5 on the highway; 11-13 in winter.

 

Average since new; 15.496. Check out my mileage chart by following the link below,

http://members.home.net/deep6blue/fuel/fuel.htm

 

I wouldn't count on that computer reading, it may be accurate in your gain, but not necessarily in the mileage. It is an estimated mileage, and I have seen quite a bit of variance.

Also, on the computer reset... if you disconnect the battery, it resets all settings to factory and as has been mentioned, it is an adaptive system, will adapt not only to your driving style, but as components experience problems it will adjust to compensate. Be aware that if you have a component that is "out of spec", the computer may have adapted to the conditions. If you unplug the system and drain the power, and the component is "out of spec", the computer may not be able to recover from factory settings (can't figure out what's going on because it is too far "out"). I had this happen to me... engine would no longer idle, it would die. So, for those of you that have a good bit of mileage, its something to think about before you pull the plug.

 

Ford97F250- I have a '99 F250 and with several mods. It didn't do jack for increasing mileage. With 265 tires, I got 11.3 city 12.3 hwy. Now with 33's, it's 10 city & 11 hwy.

I think you're gonna have to live with it. My friend at work has the same truck and year as I and he gets about 11 city. From what I read from others; the 3.73 rear gets about 1 mpg less than the 3.55.

 

I don't like reseting the computer, even when I do electrical work I don't disconect the battery. I work in the electronics field with much higher power than a 12V system and if I can do it with 5000V running trough a board than I can handle a 12V wire.

Thanks for the info guys, I'll bite the bullet and eat the gas!!

Howeber I am saving up for a package put together by www.performancecombos.com supposed to gain 90hp and 25% better mpg. We'll see.

 

I got back from my 2nd trout fishing trip this year to the Eastern Sierras and I'm happy to report an average of 16.9 mpg for the 1000 miles traveled. On my last leg of the trip from Bishop to home (Costa Mesa), the truck averaged 18.3, even having gone up to 95 mph a few times passing the 60 mph vehicles on the 2 lane portions of Hwy 395.

On my last Sierra trip in late July, I only averaged 16.4 (temps were averaging 95-105 degrees in the valleys and desert areas).

Considering that almost 25% of my driving was at altitudes ranging from 6000-9800 ft., I am extremely happy about my mileage on this most recent trip. Of course, being 2wd is helpful too!

 

i have a 97 5.4 l/df250 supercab with a 3.73 rear end, i get 12.5 in the city, 12.9 if i run super unleaded (it takes 2 tanks to kick in) and about 13.5 in the highway. my 2001 supercrew 5.4 with 3.55 rear end get 13 to 13.5 in the city.
on a side note my dad just got a new suburban and the first week of city driving got 15.5 , not even broke in yet.

 

well i just filled the tank for the first time in my 2002 f150 screw KR 4X4 5.4l v8 and i was pleasantlysurprised that i got 15.5 mpg. i never drove over 50 and it was all city driving.
of course i installed a k&n immediately when i brought my truck home. not sure if that helped or not

 

have a 2001 5.4 4x4 with 12,000 miles and have gotten at to 17.5 mpg (mostly highway but 70-80 mph) I reset the computer and ran it hard mix of town and highway and still got 13.5 mpg.

However my dad has a 98 5.4 4x4 and 12-13 would be more typical for his.