I Have An 02 5.4 And Get About 11 Mpg

 

I guess I'm lucky, 14 town & 18 hwy, but I drive the speed limit. Well most of the time!

 

My modded 4.6 F-150 with 3.55 gears got 16.2 - 16.7 MPG running 85 MPH. So yeah, something is wrong with your truck, or you're driving the pee out of it.

 

Type 3 19 lb Injectors (Improved spray pattern)$65 new on ebay.

New COP's $96 for a set of 508's on ebay(The #1 tune up for pre 03 motors). Install them on a fresh set of OEM Motorcraft plugs ..

Transgo Shift kit $90 w/F150 online discount -(keeps power to the wheels - no slipping)

Open up the Intake - outside the box and have it exit through a Magnaflow Cat Back system.

Port and Polish the TB and Elbow.

These are all fairly cheap mods that should get you at least 16 MPG in the V8's - And quite a bit more performance when you feel like havin fun

 

i think i will try that

 

did you reset the speedo for the tires

 

I get about 12-13 with my 99 5.4, and about 9 when I tow my jeep. My 97 4.6L got about 15-17 mpg. My Ram with the Hemi got 13 and that me driving like an idiot at every stop light. I was pissed at the time and thought the Hemi was a gas hog, that thing is twice the engine of my 5.4. I will never own another 5.4L, not worth the additional money for the minor amount of power over the 4.6L.

 

Damn , I wish I had a hemi - I wish I had two..... I trade both to yuh for that 5four - specialy the 99 PI 2 valve . It really must be running sh^ty after that comment above - I would still trade in a minute ..

 

I dont know maybe Im having bad luck, but so far I have had two plugs blow out of the head, 3 COP's go bad, and I still have a slight rough Idle. I love Ford trucks, I just have never been all that impressed with the 5.4L. I would have thought my fuel mileage was just a mishap, but my brother has owned several (4) F150's with the 5.4L and he gets the same mileage, my other two brother have owned 3 expiditions with the 5.4L and they get low mileage too. The very best mileage I have ever gotten was when I went to the west side of the state 70mph Cruise control the whole way there, and the whole way back 15.1mpg. That was with no more then 10 miles city driving in the tank.

 

maybe I'm lucky but I get around 16 to 17 combined hiway/town. I have found that the right foot plays the biggest role in fuel economy.

 

Well, I can honestly say I've gotton close enough to 20mpg , to call it that. We were convoying from Mich- PA . On the turn pike thru Ohio on cuise , I think we were doing 65 mph.
filled up in PA then we hit the mountaions - it was to much fun for cruise .

Last I checked it was beteween 15&16 mpg - It 's pretty much always the same no mater how I drive it usually

 

I also think i could get 20mpg if i wanted to.From SC to NY it is 1000mi and i get 17.5mpg average.That is pretty good for all of the mountains you have to go through.Oh and that is at about 85mph.

 

there is no way in hell, 11 mpg is right. the very worst i get is like 12mpg driving ***** to the wall on the insterstate. i normally get like 15-18mpg driving, and i have an 03 5.4 fx4.

 

Very first thing I would do to your truck is get rid of your COPs - Replace with the ebay $96 set - ( that price is for all 8 COPs as a package deal) Find them at Global Auto.

If Gas milage was my concern - I would replace both forward O2'S as well.

Look towards getting your motors integrity back - You have to replace all 8 COPs at the same time before turning the key the next time to set that straight.

Once that's done work you way up - IAC, EVR, EGR , TB etc. -Did mine like that about a year and a half ago . It idles smooth and also smokes the freakin 3 valve motors around here..

 

ordered cops,egr,cold air intake,and 2 new o2s. hopefully this will help