# f150 5.4 mpg question



## 7 point (Jul 7, 2019)

I have a 04 f150 5.4 it always got good mpg like around 16-17 city but in the last year it's been getting between 13-17 I'm driving the same and going the way I was before it stil runs and drives good no loss of power I haven't done any mods .anyone on here run in to the same issue?


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## model88_308 (Jul 7, 2019)

I have the exact same truck. I noticed a difference like that (but at HWY) after a tire change. I cured it. I rarely bother checking it any more.

Also, gas with  ethanol vs gas without WILL cause that exact phenomenon.


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## 7 point (Jul 7, 2019)

Do you have stock size tires on it


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## model88_308 (Jul 7, 2019)

7 point said:


> Do you have stock size tires on it



I put larger than stock on it, mileage dropped. I now have tires in between stock and the previous size (305/70/17s)


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## Mr Bya Lungshot (Jul 7, 2019)

7 point said:


> I have a 04 f150 5.4 it always got good mpg like around 16-17 city but in the last year it's been getting between 13-17 I'm driving the same and going the way I was before it stil runs and drives good no loss of power I haven't done any mods .anyone on here run in to the same issue?



Did you ever replace the spark plugs?
How many miles do you get out of a full tank and how many gallons is your tank?


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## transfixer (Jul 7, 2019)

7 point said:


> I have a 04 f150 5.4 it always got good mpg like around 16-17 city but in the last year it's been getting between 13-17 I'm driving the same and going the way I was before it stil runs and drives good no loss of power I haven't done any mods .anyone on here run in to the same issue?



      I don't have that truck,  but because of some fellow automotive techs I'm familiar with the weak points of that engine,   it could be your cam phasers have worn out/are wearing out,  they're hydraulically operated , and affected by dirty oil also,  they are controlled by the computer to adjust the timing ,    when they wear out you usually hear some noise from the top of the engine, and your timing won't be what it should be,   which can drastically change your fuel mileage.   Worn oil pumps also contribute to Cam phasers not working right.


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## 7 point (Jul 7, 2019)

The truck only has 59k miles it has a little bigger than stock tire size 265/70-17.


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## transfixer (Jul 7, 2019)

7 point said:


> The truck only has 59k miles it has a little bigger than stock tire size 265/70-17.



  Its still possible it could be timing related,  have a shop you trust check it out,  see if the timing is changing correctly,    other than that I would say check your air filter , a lot of people don't change them as often as they should,  myself included.


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## 7 point (Jul 7, 2019)

I put a new k&n air filter in it. If it's timing related would my check engine light come on ?


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## 7 point (Jul 7, 2019)

I put a new k&n air filter in it. If it's timing related would my check engine light come on ?


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## model88_308 (Jul 7, 2019)

7 point said:


> The truck only has 59k miles it has a little bigger than stock tire size 265/70-17.



My stock tire was a 265/65(70?)/18. I changed tires and wheels in '09.


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## 7 point (Jul 7, 2019)

Sorry 265/65-17 don't know where I got 70 from


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## transfixer (Jul 7, 2019)

7 point said:


> I put a new k&n air filter in it. If it's timing related would my check engine light come on ?



    Not necessarily,   only way to know whats really going on is find a good diagnostic technician and get them to check it out,   and by that I mean someone who has the scanners and equipment to check it out,,   not just some mechanic who is going to throw parts at it .


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## 7 point (Jul 7, 2019)

I will take it to my mechanic that I have used for years


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## GoldDot40 (Jul 7, 2019)

A larger diameter tire will turn less revolutions per mile...meaning your speedometer and odometer will be slower. So over the course of 10 actual miles, your odometer may only show 9.7 miles. That will add up over the course of a tank of fuel. On paper, it will certainly appear that you're getting worse mpg...when you "may" not be.

Good idea to have your speedometer recalibrated after you put bigger than stock diameter tires on it.


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## paulito (Jul 7, 2019)

I put a K&N cold air intake on my 2013 F150 and it dropped MPG. About 1.5 cuz I drove it like an idjit. I put larger tires on my 2018 F150 and it also dropped about 1.0 MPG.

I'd say it's not the truck but the changes u made. I like my big tires o. My 2018, but didnt see the benefit of the K&N cold air from the 2013, so didnt add it.


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## John Cooper (Jul 7, 2019)

I remember when I got 17-19 mpg, I get an average of 13-14 now. But I didn't buy a truck for mpg either.


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## lonewolf247 (Jul 7, 2019)

GoldDot40 said:


> A larger diameter tire will turn less revolutions per mile...meaning your speedometer and odometer will be slower. So over the course of 10 actual miles, your odometer may only show 9.7 miles. That will add up over the course of a tank of fuel. On paper, it will certainly appear that you're getting worse mpg...when you "may" not be.
> 
> Good idea to have your speedometer recalibrated after you put bigger than stock diameter tires on it.



OP, he's correct on this one. If you went up in tire size, and didn't recalibrate your speedometer, you really are not getting an accurate MPG calculation._ *Usually*_, going up in size will hurt your performance, MPG, etc.  It's just hard to say exactly how much.

What's the new tire size, vs the stock tire size?


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## fireman32 (Jul 8, 2019)

I have an 05 expedition with the 5.4, I only get around 50,000 miles out of my spark plugs.  After 50,000 it starts running bad, stuttering between 3-4 gear change and lower gas mileage.   New plugs bring it right back to good.


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## 7 point (Jul 8, 2019)

That's what I'm thinking .I haven't changed them yet


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## Mr Bya Lungshot (Jul 8, 2019)

7 point said:


> That's what I'm thinking .I haven't changed them yet



Watch all the 5.4 plug removal videos, do them one at a time with the engine hot.
I used sea foam to soak them. 
Blew out debris. I used a ratchet with care. If it squeaks it’s coming whole.
It will squeak until it breaks.
I used anti seize to replace them with the updated one piece welded Oem motorcraft. Didn’t break any but had the brand new lisle tool on hand just in case.
Did it myself. The 2004 is probably the worst for breaking plugs in half. The longer you wait the more stuck with carbon they get. Once done you’ll be relieved and will never have that problem again. If it shudders between 40-50mph that’s a coil over pack.
Use Oem for best results.
It’s up to you how long and how many miles you wait. Some people use an impact to break the carbon loose.
The one on the passenger side behind the computer was the hardest to get to so I removed the computer for clearance.All eight came out unbelievably easy and unbroken.


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## fireman32 (Jul 8, 2019)

I bought mine used with 95,000 on it.  I bought the lisle tool also to be safe. Watched the videos and did everything possible to not break one, wound up breaking two.  The tool worked flawlessly.  The one behind the computer and front driver broke with me. Liberal amounts of anti sieze is applied every time I change them.  It’s a breeze now, new coil packs last change.


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## fireman32 (Jul 8, 2019)

Mechanic quoted $400, I did it for less than $200 with buying the tool.


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## 7 point (Jul 9, 2019)

My mechanic said the plugs are good for 100k miles .but I think it's times to change them


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## 7 point (Jul 9, 2019)

Mr Bya Lungshot said:


> Watch all the 5.4 plug removal videos, do them one at a time with the engine hot.
> I used sea foam to soak them.
> Blew out debris. I used a ratchet with care. If it squeaks it’s coming whole.
> It will squeak until it breaks.
> ...


Mine shutters at about 70 mph


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## Mr Bya Lungshot (Jul 9, 2019)

7 point said:


> Mine shutters at about 70 mph


Spark plugs. 
Run some sea foam through your gas tank to loosen the carbon before you change them. At least one of your plugs is going bad.
Watch as many videos as you can especially the ones who claim not to have broken any plugs. Start looking for the lisle tool now.
Some places will rent it. Try Napa.


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## 7 point (Jul 12, 2019)

I'm going down after work to have a scanner plugged in and go from there .hears a pic of the truck for John cooper.


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## 7 point (Jul 12, 2019)

I just came from the shop it showed no codes I took him for a ride he siad to just run some seafoam in it and blow it out and see if it smoothes out


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## John Cooper (Jul 13, 2019)

Run the seafoam even with the low miles you could still be having Plug issues. Beings that is an 04 you could have some COP boot and or spring issues too. 

If you have kept the oil changed regularly, and used a FoMoCo filter, I doubt phasers. 

What oil have you been using? I only use the FoMoCo oil and filter and change every 3000 miles.


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## Mr Bya Lungshot (Jul 13, 2019)

My shudder started at 70mph on the money every time and went away soon as I changed plugs. 40-50 was a coil pac. Left it too long and it burnt my catalytic converter driver side. Light would flash but went away for good once changed both cop and converter.
I had changed oil the week before (Mobil one and Mobil one filter} full synthetic. I noticed my gas mileage was less also until I changed the plugs. Don’t wait and break one later. Your starting to have an issue with one plug now so don’t beat around the bush knowing the plugs NEED changed. 70 mph on the money was a plug electrode barely worn down. New plugs and ran 94mph like new. Err I mean it woulda.
Clean the mafs yourself but that didn’t help anything.
YouTube videos are simple maintenance and non mechanic friendly.
If you wait for 100,000 miles to change a 2004 F150 5.4 spark plugs then you wish you hadn’t. I went to a junkyard and practiced on their motor first... still never broke one. I felt bad putting it back it ? 
I’ve swapped my transmission also because I did not maintain it.
Don’t believe in lifetime fluid. I do use ford trans fluid. Mobil one oil.
If there is a 5.4 video I’ve watched it twice.
All these trucks do the same and fix the same. Change your plugs per the videos. Scotty Kilmer rev your engines helps a lot and occasionally 
Bull....korner knows his stuff too. Have at it and do you own maintenance. Oem welded updated plugs with anti seize and your headache will go away for good on that note.
Do it hot for each plug one at a time. Comes right out.


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## 7 point (Jul 13, 2019)

I went to wally world got some seafoam and motorcraft oil and filter .I have been running valvoline max life blend .I'm going back with all oem it does have a k&n air filter


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## John Cooper (Jul 13, 2019)

Is you K&N just the filter or complete cold air intake?  

I still say you have a plug issue or a coil pack boot/spring issue.


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## 7 point (Jul 13, 2019)

It's a drop in filter .I'm leaning that way too but I'm doing the cheap simple things 1st and go from there


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## Mr Bya Lungshot (Jul 13, 2019)

Nothing wrong with your valvoline max blend at all. Today’s oil are not much difference in the next except mainly price. I’ll never use motorcraft brand oil or filter. I do use motorcraft trans fluid.
I want some oil from an oil company not a car company.
One very knowledgeable trusted professional mechanic online says to put 5w30 instead of 5w20 in the ford 3v ASAP if you want that motor to last.
He says the oil pump is a bad design and should be upgraded to high volume melling??? Just sayin. Have not done either yet.
Afraid to just as you are about the spark plugs breaking.
The Oem oil pumps are failing I guess. Dang what a design.
In fact our oil pressure gauge reads fake and not actual.
Notice it never changes it’s reading except when you drain and replace the oil it hesitates an extra millisecond.


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## 7 point (Jul 13, 2019)

Dang ...... I'm getting scared of it now .might be time to trade it on a new Tacoma and get 20 mpg .


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## John Cooper (Jul 13, 2019)

7 point said:


> It's a drop in filter .I'm leaning that way too but I'm doing the cheap simple things 1st and go from there



I am not a real fan of K&N seen to much bad things with them, that being said their drop in are a little better than their CAI. 

There are mixed stories and several thousand post about oil in the 5.4 3V. I run the FoMoCo in mine cause I have a brand new FoMoCo reman eng in mine and have 2 years left on the warranty and if it fails I don't want Ford to be able to say I didn't run the right oil. With your mileage I doubt you have oil pump issues. 

Go join ford f150 forums and post you question there, there are some guys with our generation trucks that are pushing 300,000 miles and have no issues. 

Check out fordmakuloco on YouTube, he probably knows as much if not more than anyone on the 5.4 3V   

It seems by 08 ford had fixed most of the problems with the engine, that's why I went the ford reman route with my engine. Their remans are all updated to 08 and newer specs. 

I would try and figure out what's going on with your engine if it were me, also one other thing I just thought of to check is your FPDM (fuel pump driver module) it's on the frame back by the spare, might have to drop the spare, they are known to  cause problems also and an easy fix.


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## John Cooper (Jul 13, 2019)

Your fix may be simple and simple is way better than a new truck payment in my opinion.


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## 7 point (Jul 13, 2019)

I like the truck it's been in my family sence new my mother bought it in 04 brand new been in her garage sence the day she drove it home I've had it about 2 years now


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## John Cooper (Jul 13, 2019)

7 point said:


> I like the truck it's been in my family sence new my mother bought it in 04 brand new been in her garage sence the day she drove it home I've had it about 2 years now



There you go. Keep digging you will figure it out!  Find a good reputable ford tech that knows 5.4 3V engines. He should be able to help you out.


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## Mr Bya Lungshot (Jul 13, 2019)

fordmakuloco is the one who says use 5w30 oil instead and recommends the oil pump swap. Sounds as if @John Cooper watches his maintenance and rebuild videos too.
I agree ? % with John.
I do wonder what happened to your original motor if not too painful to tell.

Only thing is my Fpdm is not where it’s supposed to be.
Never even seen it under there....
Haven’t had a need to pin it down either though.
Maybe I over look it.


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## John Cooper (Jul 13, 2019)

Mr Bya Lungshot said:


> fordmakuloco is the one who says use 5w30 oil instead and recommends the oil pump swap. Sounds as if @John Cooper watches his maintenance and rebuild videos too.
> I agree ? % with John.
> I do wonder what happened to your original motor if not too painful to tell.
> 
> ...



I bought my truck used and went against everything I have ever done/preach/believe in. I sunk money into the lift kit and tires(because the only thing my scanner would pop was the CEL was on because the cats had been removed) drove it for 2 months  before I changed the oil!! Usually first thing I do is oil change!!!!!

So I change it with 5-20 drive less than a mile and it's going crazy, skipping rattling and such, no big deal till I pull it in the shop. Remove the front cover and some one had done chains, phasers and tensioners. But the crank was walking in and out over an inch due to thrust washer failure. Also the front cover was almost worn through from the crank walking. Since I work at big truck dealer who also sold ford trucks I ordered a ford reman. 

Maintenance is the key to these engines, if ford say 5000 oil change I do 3000. These things are built to such tight tolerances you have to stay on top of maintenance!


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## ribber (Jul 14, 2019)

7 point said:


> Dang ...... I'm getting scared of it now .might be time to trade it on a new Tacoma and get 20 mpg .



I would get rid of the truck, like yesterday. The 5.4 3 valve is the sorriest engine Ford ever made IMO. Had a 2006 myself and all the same problems, and after regular maintenance and never abusing the truck whatsoever, it dropped a valve on #3 cylinder. People change cam phasers, timing chains, VCTs, etc. and it will never 'fix' the engine because the root cause is a weak oil pump. Like said above, the oil pressure gauge is not a gauge. It only takes 7 psi to make it read. Most mechanics around here won't fix the engine, but will swap to a Jasper engine, which is a good one so I'm told. But, it's @$7K installed.


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## 7 point (Sep 16, 2019)

I just dropped it off at the shop getting plugs done he said he would change the fuel filter too.driving the ole yota woods truck to work in the morning .


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## 7 point (Sep 22, 2019)

I got my plugs done the shutter is gone it runs like a new truck .not shure about the mpg yet I checked it this week got my plugs done Tuesday filled up Sunday after church I got 14.8 this week about the same as before.


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## 7 point (Oct 22, 2019)

Update .the truck still runs good after getting the plugs done but my mpg is still 13-14 mpg I'm just about to believe that's what I'm gonna have to live with.


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## John Cooper (Oct 22, 2019)

7 point said:


> Update .the truck still runs good after getting the plugs done but my mpg is still 13-14 mpg I'm just about to believe that's what I'm gonna have to live with.


That's all I get out of mine, but it's lifted with bigger tires also. Have you changed the fuel filter lately? How bout the air filter?  I didn't read back through the whole post again so I apologise if you already answered these questions.


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## 7 point (Oct 23, 2019)

The fuel filter was changed when the plugs was the air filter is a k&n drop in .yours is getting about right for what it is mine is 2wd with just a little bigger than stock tires .


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## Mr Bya Lungshot (Oct 23, 2019)

7 point said:


> Update .the truck still runs good after getting the plugs done but my mpg is still 13-14 mpg I'm just about to believe that's what I'm gonna have to live with.





7 point said:


> The fuel filter was changed when the plugs was the air filter is a k&n drop in .yours is getting about right for what it is mine is 2wd with just a little bigger than stock tires .


Glad to hear your plugs are done.
Did any break?
By now I bet your relieved but you’ll get better gas mileage from the non ethanol fuel. Mines 2wd and stock tires.


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## 7 point (Oct 23, 2019)

Non broke thank the lord .What kind of mileage do you get?


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## John Cooper (Oct 24, 2019)

7 point said:


> The fuel filter was changed when the plugs was the air filter is a k&n drop in .yours is getting about right for what it is mine is 2wd with just a little bigger than stock tires .


It honestly could be the larger tire size, I have a tuner and programed my gear ratio and tire size so my speedo and odometer are reading right. If the tire size and stuff don't match you fuel economy won't be right!!!!


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## 7 point (Oct 29, 2019)

It's got 265 on it in stead of 255  it's just one side up


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## John Cooper (Oct 29, 2019)

7 point said:


> It's got 265 on it in stead of 255  it's just one side up


That will throw your mileage off a little, maybe a mile a gallon at the most. Are you figuring your mileage with pen and paper or going by the trucks computer.


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## 7 point (Oct 29, 2019)

Pen and paper miles ÷in to gallons


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## John Cooper (Oct 29, 2019)

7 point said:


> Pen and paper miles ÷in to gallons


I know on the f150 forum alot of guys are getting close to 19.  Sure wish I had the answer for you. 

I know mine will never much better than now, but I think yours should be.


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## GoldDot40 (Oct 29, 2019)

7 point said:


> It's got 265 on it in stead of 255  it's just one side up


What's the complete size of the tire you're running? 265/??-16? And what's the stock tire size?


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## 7 point (Oct 31, 2019)

John Cooper said:


> I know on the f150 forum alot of guys are getting close to 19.  Sure wish I had the answer for you.
> 
> I know mine will never much better than now, but I think yours should be.


It uses to get around 17 in city and 23 on hiway guess it just got thirsty in its old age


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## 7 point (Oct 31, 2019)

GoldDot40 said:


> What's the complete size of the tire you're running? 265/??-16? And what's the stock tire size?


265/65-17 is what I have now roughly 31" tall not sure of the complete size of the original ones.


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## Roger74 (Nov 1, 2019)

I've got the same engine in my older F150 (125k miles).  Mileage may drop over time as the engine gets loose.  But that's too few miles for that to happen.  If you changed tire size the odo is off so your math is off now to. Also check your tire pressure - that makes a big difference.


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## 7 point (Nov 1, 2019)

I did check my tire pressure. I've tryed driving different  (taking off slower maintaining a steady speed ) nothing seams to change anything.


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## C.Killmaster (Nov 9, 2019)

I've got 230k miles on my 2007 and it gets 15.4 mpg.  My mechanic says it's a really solid engine once you get the spark plugs changed.  Mine had the cam phaser ticking and my mechanic said to run 10w30 for a while.  Once I did the ticking stopped, I ran 10w30 for a few oil changes then back to 5w20 and the ticking never came back.  That was 30k miles ago.  I'm running full synthetic oil now too.


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## 7 point (Nov 9, 2019)

I checked my mpg the last couple tanks it's about 15-15.5 I'm happy with that .


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## bruiserbuckgrower (Jan 15, 2020)

transfixer said:


> I don't have that truck,  but because of some fellow automotive techs I'm familiar with the weak points of that engine,   it could be your cam phasers have worn out/are wearing out,  they're hydraulically operated , and affected by dirty oil also,  they are controlled by the computer to adjust the timing ,    when they wear out you usually hear some noise from the top of the engine, and your timing won't be what it should be,   which can drastically change your fuel mileage.   Worn oil pumps also contribute to Cam phasers not working right.



To add to this I have a 2010 f150 with the 5.4 and more times than not it is showing or possibly even throwing a code for the cam phasers when in all actuality it is the vvt or vvt solenoid screens that are stopped up. If the truck cranks up runs normal a few minutes and then acts really funny with the rpms dipping really low, especially when stopped at a red light, it's more than likely the solenoid and not the cam phasers. I went round and round with several mechanics and 2 ford dealerships telling me I needed to replace the cam phasers and timing chains and i simply refused to believe them. If it is the phasers it should be doing stupid stuff at every rpm not just an idle. There is an easy test to check this by simply unplugging the vvt solenoid and if the trucks idle events out instantly it's the solenoid not the phasers. The solenoid has a screen that gets stopped up (sounds backwards) but essentially dumps to much oil to the phasers at low idle and it tries to choke the truck off, it throws all sorts of codes leading one to believe it is the cam phaser, the giveaway for vvt is if throws the "over retarded code" (no ****) which in turn throws the cam code, usually a bad bank code and another actuator code. From 04 to 08 it is an easy fix, 09 and 10 you have to remove the valve cover to pull the solenoid 

This does not sound like the OP's problem but ford has replaced many unneeded cam phasers for 1600-2400 shop bill when a 100 dollar part is all that is needed. And guess what comes with fords cam phaser kit, shiny new vvt solenoids.


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