Notices
2004 - 2008 F150 2004, 2005, 2006, 2007 and 2008 Ford F150's with 5.4 V8, 4.6 V8 engine
Sponsored by:
Sponsored by:

serious decrease in gas mileage

Thread Tools
 
Search this Thread
 
Old Oct 31, 2008 | 10:25 PM
  #1  
ggwash21's Avatar
ggwash21
Thread Starter
|
Senior User
Joined: Aug 2003
Posts: 393
Likes: 2
serious decrease in gas mileage

I went from getting 18-19 mpg to 14-16mpg on highway and i have done nothing different to my driving. i have replaced the fuel filter and ford rebuilt the tranny since i have noticed the decrease in mileage???? btw its a 2004 F150 FX4 5.4l 3v supercab with 57k Any ideas? i was thinking about changing plugs. I have only had this truck since 51k and new to ford and to be honest dont know where the plugs are lol anyways Any pointers or ideas on why such a decrease would be helpful
 
Reply
Old Oct 31, 2008 | 11:28 PM
  #2  
DonsFx4's Avatar
DonsFx4
Elder User
Joined: Jan 2004
Posts: 752
Likes: 0
From: Marple Township, PA
Depending on where you live, you could be getting winter-blend gas already. I've experienced the same drop around this time of year before. I don't know the exact reformulation, but MPG typically plummets once there's frost on the pumpkin (and I don't mean the rear diff!)
 
Reply
Old Oct 31, 2008 | 11:33 PM
  #3  
Ford Fx4's Avatar
Ford Fx4
Laughing Gas
20 Year Member
Liked
Loved
Community Favorite
Joined: May 2006
Posts: 1,211
Likes: 69
From: land of 10,000 lakes
Check for a sticking parking brake...I believe there was a TSB for this on 04-05's and some 06's
 
Reply
Old Nov 1, 2008 | 06:34 AM
  #4  
svt2205's Avatar
svt2205
Posting Guru
Joined: Mar 2004
Posts: 1,195
Likes: 0
From: Sunapee NH
I'd say it's winter gas and colder temps that are the likely cause for your mileage drop. 17 to 15 is what my truck drops to here in NH.

Now if you live in a warm climate, I'd wonder if that drop was based on a single tank or a few tanks of gas. Could just be a crappy batch of gas.
 
Reply
Old Nov 1, 2008 | 08:39 AM
  #5  
Matt983's Avatar
Matt983
Senior User
Joined: Nov 2007
Posts: 210
Likes: 0
From: Kingwood, TEXAS
before you attempt to change the sparkplugs do some searching through older posts, seriously. For some people, myself included what used to be a simple spark plug change can turn into an expensive nightmare fast. Just thought you should be forewarned. Hope you figure out the drop in MPG too.
 
Reply
Old Nov 1, 2008 | 09:02 AM
  #6  
98greensi's Avatar
98greensi
Senior User
Joined: Dec 2007
Posts: 256
Likes: 0
From: Sudbury, Ontario
I wonder if it can be as simple as a dirty air filter?, have you replaced it or checked it lately? when i went to B.C. from ontario i got around 18mpg average and on the way home changed the air filter and slowed down alittle bit and got 20 most tanks
 
Reply
Old Nov 1, 2008 | 09:30 AM
  #7  
ggwash21's Avatar
ggwash21
Thread Starter
|
Senior User
Joined: Aug 2003
Posts: 393
Likes: 2
i have replaced air filter fuel filter oil change (amsoil) right after i bought it. Only thing i'm thinking is i'm out in the dakotas working and they have that 10% ethonal junk which is 89 oct and i ran one tank of that and went back to 87 unleaded but have ran 3-4 tanks through it since then. One thing i'm gonna do is have the dealer change plugs when time comes. thanks guys i will do some more research on this also
 
Reply
Old Nov 1, 2008 | 11:25 AM
  #8  
Tylus's Avatar
Tylus
MMNC (SS)(Ret)
Veteran: Navy
20 Year Member
Photogenic
Photoriffic
Joined: Mar 2004
Posts: 11,606
Likes: 151
From: SE Georgia
Club FTE Silver Member

sounds like its the gas that is your problem.


you get good MPG during summer months, and then the winter blends show up...I can normally expect about a 2 mpg drop with that stuff
 
Reply
FTE Stories

Ford Trucks for Ford Truck Enthusiasts

story-0

Every 2026 Ford Engine Explained

 Brett Foote
story-1

10 Ugly Ford Trucks That We Still Kinda Love

 Joe Kucinski
story-2

10 Things Every Truck Owner NEEDS (2026 Edition)

 Michael S. Palmer
story-3

Rezvani's Latest Post-Apocalyptic Monster Is a Ford F-150 Raptor Underneath

 Verdad Gallardo
story-4

Top 10 Most Expensive Ford Trucks Ever Sold on Bring a Trailer

 Joe Kucinski
story-5

2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)

 Brett Foote
story-6

Top 10 Ford Truck Tragedies

 Joe Kucinski
story-7

AEV FXL Super Duty - the Super Duty Raptor Ford Doesn't Make

 Brett Foote
story-8

Lobo Vs Lobo: Proof the F-150 Lobo Should Be Even Lower!

 Michael S. Palmer
story-9

Ford's 2001 Explorer Sportsman Concept Looks For a New Home

 Verdad Gallardo
Old Nov 3, 2008 | 08:00 PM
  #9  
m825smoke's Avatar
m825smoke
Freshman User
Joined: Sep 2006
Posts: 38
Likes: 0
From: Colorado
before i got stationed in Colorado, i was in the Carolinas, had a 04 4x4 f150 screw, had a CAI and an edge programmer, i was getting around 18 in the city and 20 to 22 on the highway. well got moved out to Colorado, started getting 14 to 15 in the city and 17 to 18 on the highway! thought i was going crazy, then i noticed that this tree hugger state's got E85! it's got alot to do with the fuel your state is saling!! Any way check the gas. I since traded my old F150, got an 08 f150 4x4 screw lariat, get arounf the same mileage, except when i get the high octane which is 91 here, or i put the injector clean in. So i got another CAI and a programmer on the way, should be here in about a week, will let you know more after it comes in.
 
Reply
Old Nov 3, 2008 | 08:46 PM
  #10  
ggwash21's Avatar
ggwash21
Thread Starter
|
Senior User
Joined: Aug 2003
Posts: 393
Likes: 2
Ya i figured it out...... these farmers in North dakota got on their knees for the good ole oil company and now the 87 here has 10% ethanol go figure..... cheaper by 15 cents and burns more.... i'm gonna start running higher oct if it means my gas mileage back.....
 
Reply
Old Nov 3, 2008 | 10:15 PM
  #11  
Ryan50hrl's Avatar
Ryan50hrl
Post Fiend
Joined: Nov 2001
Posts: 7,698
Likes: 4
From: Neenah, Wisconsin
winter blend i'm pretty sure showed up here two weeks ago....my gas mileage dropped 1.5 mpg
 
Reply
Old Nov 3, 2008 | 11:12 PM
  #12  
ranger56528's Avatar
ranger56528
Senior User
Joined: Jan 2006
Posts: 140
Likes: 0
From: Dent,Mn
I run 87 with 10% eth and I get 16.8-17.5mpg with my 08 screw 4x4 5.4 Ive also gotten better mpg when I drive long dist with cruse on.....
 
Reply




All times are GMT -5. The time now is 02:38 PM.

story-0
Every 2026 Ford Engine Explained

Here's everything you need to know about every Ford engine available for the 2026 model year.

By Brett Foote | 2026-06-05 12:58:01


VIEW MORE
story-1
10 Ugly Ford Trucks That We Still Kinda Love

Slideshow: 10 ugly Ford trucks that we still kinda love.

By Joe Kucinski | 2026-06-03 09:51:16


VIEW MORE
story-2
10 Things Every Truck Owner NEEDS (2026 Edition)

Slideshow: the best gifts for dads & grads

By Michael S. Palmer | 2026-06-03 15:43:58


VIEW MORE
story-3
Rezvani's Latest Post-Apocalyptic Monster Is a Ford F-150 Raptor Underneath

Slideshow: Called the Fortress, the 850-horsepower pickup combines Raptor underpinnings with military-inspired features, survival equipment, and a starting price of $285,000.

By Verdad Gallardo | 2026-06-03 11:38:36


VIEW MORE
story-4
Top 10 Most Expensive Ford Trucks Ever Sold on Bring a Trailer

Slideshow: 10 most expensive Ford trucks ever sold on Bring a Trailer.

By Joe Kucinski | 2026-05-27 16:24:34


VIEW MORE
story-5
2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)

Here's everything that has changed for the latest model year.

By Brett Foote | 2026-05-27 16:17:28


VIEW MORE
story-6
Top 10 Ford Truck Tragedies

Slideshow: Top 10 Ford truck tragedies.

By Joe Kucinski | 2026-05-18 19:34:33


VIEW MORE
story-7
AEV FXL Super Duty - the Super Duty Raptor Ford Doesn't Make

And it might be even better than that.

By Brett Foote | 2026-05-18 19:26:42


VIEW MORE
story-8
Lobo Vs Lobo: Proof the F-150 Lobo Should Be Even Lower!

Slideshow: Does lowering an F-150 Lobo RUIN the ride quality?

By Michael S. Palmer | 2026-05-18 19:20:37


VIEW MORE
story-9
Ford's 2001 Explorer Sportsman Concept Looks For a New Home

Slideshow: Ford's bizarre fishing-themed Explorer concept has resurfaced after spending decades largely forgotten.

By Verdad Gallardo | 2026-05-12 18:07:46


VIEW MORE