Ruthless Robbie

For over a year now my truck has been getting high 14's for mpg. It doesn't matter if I drive during 100 degree heat in the summer or freezing temps in the winter it gets the same. My truck is completely stock and ever since I've purchased it I've filled it with super unleaded 93 octane.

I'm wanting to say that I used to get high 16's over a year ago but I took it to the Ford deal because the transmission shifted so hard a couple of time it felt like I had gotten rear ended by an 18 wheeler. The dealer kept it a day and called me to pick it back up. They said they couldn't reproduce the problem and everything ran fine so they gave it back. They said they didn't do anything at the dealer but I think they may have messed with the computer maybe? I don't know.

Anyways, I drive mostly highway, rarely do I drive in the city and I can only get high 14's. For those who will ask, it's a 2011 completely stock supercrew FX-4 with almost 50,000 miles.

Any suggestions?

Tothemax

Are you hand calculating that mileage or going of the computer?

All maintenance up to date?

NASSTY

Change your spark plugs and gap them to .030 . Ski Smuggs said his plugs were gone @ 35k miles.

BlueFlameMetallicFX4

Listen to this advice^^^...and swap your plugs out with SP534's (or the brisk plug)

Just changed mine, all were worn to .42 and two had cracked ceramic casings, one had a piece fall off when I removed it from the socket.

Got my mileage back to 16 city 20+ highway, my truck feels like it did when I bought it.

And don't forget to clear out the PCM when your done:courtesy of Makuloco2000
Makes a world of difference...

Joewee3.5

Are you driving 80+mph? If not, do what everyone is saying above.

maplelakeduckslayer

Is highway 60 mph or 80 mph? I get 22 at 60 mph and 14 at 80 mph.

zx12-iowa

That when you are flying past the outlet mall or stuck in outlet mall traffic? Lol.

Ruthless Robbie

Maybe that's it, I hit cruise control at 75mph. I will also change the spark plugs once I hit 50k which will be in 2 weeks. I know when I bought it new I cruised at 75mph and if I recall I got 17mpg.

egbertnr

i have what sounds like the same truck as you. 2011 FX4 SCREW with 6.5 bed. FOr those who dont know, its a 3.73 ratio too since thats all we could get back then....but all winter I and even the better part of last year I was getting very poor mileage. When the truck was in that 5-10k range I could pull down 18mpg on back roads. Over the past year or so I was getting more like you at 14. I recently changed my plugs, cleaned my intake, and added a catch can and I am seeing better mpgs. I currently drive very short trips so I tend to see 15-15.5 mpg with repeated short trips but when I throw in a few highway trips it goes up a good bit as well. Now I say this with great hesitation as to not start conflict in yet another thread, but I have seen better mpgs with those mods. I would start with the plugs first if I were you just because mine were so out of wack. I have seen a difference too when I run my 93 perf tune vs stock tunes. 93 perf is much better comapred to stock for mpgs oddly enough and thats me keeping my foot out of it all the time.

Hope you figure it out. I have never seen anything higher than 18 in any conditions as of right now. But then again I dont do a lot of highway.

SkiSmuggs

Do you ever reset the Eco gauge? Once you've got several hundred or thousands of miles on it, you would have to get 20 mpg for a long time before it would go up to 14.8 from 14.7. I reset mine when I change tunes, before a long trip, etc.
Short trips absolutely kill fuel mileage and should be avoided if you can. I drive the winter beater into town and back and use the truck for 20+ mile trips.
Cold weather drives down MPG also. We had a brutal winter and my mpg was in the upper 16s with below zero to single digits. Now that we get above freezing during the day, I am at 19 or more.
If you are stock, I found the canned 87 or 91 SCT tune with premium gas delivers good economy and makes the truck drive better.