97 5.4L Expedition Mileage

[JozifG]

Right now I am getting 10.2 MPG with 90% city and 10% highway driving. My 1997 Eddie Bauer has 157k miles. Now I know this car isn't brand new, but damn, you would think I could get at least 12 MPG. It's pretty much stock besides a K&N Cold Air Intake (which did not increase my MPG). No matter how economically I drive, my MPG doesn't go up.

I checked my air filter, checked tire pressure, and even replaced the PCV valve (which accually caused my MPG to drop a little). The only thing that seemed to help was running a can of Seafoam through the gas tank (which upped my miles per gallon by 0.3). What are other people getting right now with similar miles? What else can be done to help?

 

[pronstar]

I would clean the throttle body.
At your age/mileage, it's likely gunked-up in there. May halp MPG a little.

Here's a good how-to:
http://www.fordf150.net/howto/throttlebodyclean.php

Also, how old are your O2 sensors?
If they are original, I'd replace the upstream ones. They tend to gradually degrade over time, and won't always throw a code until they are completely dead.

I get 12mpg in mixed/city driving, and 14mpg on the highway....and that's driving like an idiot with a supercharger and 4.10s on street tires.

 

[JozifG]

Thanks, I'll give my oxygen sensors a look and if I have some time, I'll give my throttle body a cleaning. I appreciate your help.

 

[thereason21]

I got a 97 Expy EB with 126k on it and i am currently getting 12.2 per tank. Thats with week driving to work and back only and weekend running around in town or what ever. I have no mods but am working up a list as we speak.

 

[Burnrubber1]

mine is a '99 EB and I get 13.0 MPH with 132K on the odometer.

 

[mustangrfast88]

my 2000 with the 5.4 and all wheel drive all the time get right at 12.90 -13.30 mpg and it has got better since i seafoamed it and changed some maintance parts trying for 15-19 mpg when its all said and done

 

[Patrick]

got a 2000 also with a 5.4. when i first got it, got only about 10 to 12mpg. installed a CAI and didn't see much of a difference. But i read about changing the fuel filter and THAT made a huge difference. i drive a bit more conservative now but with 70 miles round trip to work, 30 miles throught the city with stop lights every 100 yards so it seems, and about 40 miles on a two way hilly road inow get 15 to 16mpg.

when i tow the boat, 19ft, i get about 12MPG

 

[pronstar]

i get about 12MPG [/B]

That's not bad at all.
I'm into the single-digits when I tow.

 

[JozifG]

So the upstream oxygen sensors are the two closest to the front of the truck?

 

[wrangler45337]

I have a '99 EB with the 5.4 and 82,000 on the ticker. I only get 11.8 or so but I drive like a madman sometimes. Even when I drive really easy it still sucks gas, but.......hey I bought it knowing the kind of mileage. Not to worried about it, because I am planning on Heads, TB, MAF, Intake Elbow, Cams, Electric Fan and Water Pump, Headers, and Exhaust, and a set of 285-75R17 Mud Terrains. Just have to finish saving my pennies. We'll see how bad the MPG gets then!!!!!