I have a 2005 F150 SuperCrew 5.4L V8 with 3.73 gears and I get 13.5-14.5 city and about 18.5 highway. The only thing I added was an edge evolution which I run in tow haul mode and helped the mileage a little. I would probably do better if I keep my foot out of it.
There were issues with the spark plug removal and cam phasers in some trucks. Just search on here and you will find numerous threads on the issues.
My previous truck was an '08 F150 S'crew, 5.4L with 3.55 rear end. It would consistantly get 15ish in city driving, 10-13 towing, and 20+ steady speed on the highway, depending on the speed. One highway trip I got 24.5 consecutively on 4 tankfuls with cruise set at 102km/h. That was a once in a ownership experience.
**Disclaimer**I am Canadian, the figures I've posted are hand calculated using the Canadian Gallon, which is 4.54 liters, vs 3.87 liters in the US gallon.
I get 14-16 in average mixed city/highway driving on commute of 30 miles. I drive conservately. Drove 2000 miles roundtrip during Christmas break driving 75-80 on freeway, got tad over 16 mpg. I do get 17-18 mpg cruising on country roads no faster than 65 mph.
At least it's improvement over the previous generation in 2002.
14 city. 15.5 to 16 at 75 mph. Highway. 5.4 Triton. 3.73 gears. Cow guard, 18 inch rims. Haven't checked highway since install of bed cover last winter. 78300 miles. Check cam phasers. Mine are new ones. You will know when they are loose. New plugs.
Listen carefully to that 2004...if it sounds like a diesel...then look into the cam phaser issue.
Exactly!! If is sounds like one DONT get it. If you do, then prepare on ripping valve covers off and replacing lash adjusters, cam phasers, tensioners, etc....
My last 04 DID sound like a diesel, my current one does not. just youtube 5.4 cam phaser to know what to look for. Dont mistake it for loud fuel injectors (these trucks have loud fuel injectors)
Other than that, alot of people get alot of miles out of them. When i was looking here were my things to look for as I read they are notorious problems on these trucks
1)Cam phaser diesel noise
2)Exhaust manifold leaks (which I now have), mostly on passenger side. you can tell if you hear a ticking noise on acceleration
3)Bed shake, make sure it doesnt shake too bad going down the highwy at cruising speeds (my last one did, drove me crazy)
4) Make sure all power windows work, regulators suck in these trucks (just replaced one)
5)Tranny shudder - almost every F150 i drove had a slight shudder when releasing pedal and reapplying it
6) If buying from a dealer, MAKE them change spark plugs before buying. If not it sucks and cost alot to have to change. just google 04 f150 spark plug issue (the plugs are notorious for seizing in the heads)
Other than those few items, these trucks are great and not all of them get these issues, but after reading up on the forums, these are the most common issues to look for
My previous truck, 2001 7.3l powerstroke 4x4, blew my current truck out of the water as far as mpgs went. It consistently got 17 mpg no matter how you drove it. My f150 gets 14-16 on a good day. I do have 35 inch tires though. As far as the cam phaser tick, with it being an 04 it probably has already been fixed depending on miles. Listen to it run and you will know whether or not it has.