After driving my Nissan Armada on a couple long trips, I was thrilled to get rid of it and pick up my 2005 F150 4 dr Lariat 4x4 with the 5.4. I love the truck but much to my surprise, my mileage is no better than the Armada! I have been averaging 12.1 around town (not too bad), but I am only pulling 13 to 13.5 on road trips (freeway). I was expecting closer to 17+. My old Yukon XL with the 5.3 would regularly get 19+ so a little disappointed. Is this consistent with others or do I need to start looking into whats going on?

 

I used to get 12 city/12.5 hwy, with a few aftermarket add-ons I'm now getting 13.8 city/15.1 hwy. Some people on the forums get way better milage than I do with stock trucks, but my lower mileage is probably due in part to my lead foot. I spent around $1,400 to modify my truck, but the savings in fuel will pay for cost within 12-18 months. Driving habits really show with this truck.

 

That's the worst mileage for a 5.4 in an F-150 I have ever heard of. Around town (06 F-150 SCab 5.4L), I easily get 15 and driving the highway at 65 it gives me 19.5 and about 16/17 on the freeway cruising at 75. Try driving at or less than 2000 rpm. Yes, that is a little slower off the line than you are probably used to but a light right foot makes for a tremendous improvement in mileage. Hows your tire pressure? Do you carry much of a load in day to day driving?

One fairly inexpensive improvement you should add is a Scan Gauge(Google them). They are about $150 and will pay for themselves in just a few months with the improved mileage. My first trip towing our trailer I increased my mileage from 10 to 11.3 (9%), just by paying attention to the average and real time mpg data from the Scan Gauge. Everyday non towing mileage went up as well. Most folks find 8 to 10% mileage improvement with the Scan Gauge and it reads dozens of other engine functions along with being a built in code reader. Best $150 I ever spent on any vehicle. Good Luck!

 

my hwy mpg sucks as well. not much better than my city.

 

First off, I would definitely agree with the stay below 2k rpm and mileage will significantly increase!

However you also may want to check your gears because I have a '06 F150 XLT Scab (half rear doors) and a long bed with the 5.4L V8, and I have 4.10 gears in the rear with 7-lug wheels. It's the HD option I guess but it completely kills my mileage. I have big tires (35") and only get about 10.5-11 typically, but even with stock tires I only got 11.5-12.5. Good luck!

 

Gearing and tires make a huge difference. I should have mentioned that I am running Limited Slip 3:55's. My Tires are Michelin M/S 2, E rated LT's 265 70 17's that I run at 60 PSI. Since about half of my miles are towing these tires work very well and still give an excellent ride. They probably cost me about a third of an mpg due to the weight but the enhanced towing performance was well worth it.

 

Just recently joined up, and I have a 2006 xlt with Magnaflow exhaust and I just ordered a K&N CAI, I was wondering what tuner to go with. I like the Edge but am torn between the hypertech energy, and the Superchip. How is the Banks working for you? I almost ordered the tuner with the CAI but thought I should wait and see what it actually does I recently upgraded wheels and tires to 18"s so I wanted to change shift points and tire size. What would you suggest.

 

I went with the banks for three reasons. First, I had previous experience with Banks with my 98 Powerstroke and liked the product results. Second, I wanted a package that was designed to work together on my vehicle. Third, Banks tunes are are considered conservative/safer overall in comparison to other tunes, especially in the diesel realms. I wanted power/performance gains and I got both and I am very happy except the lone exception of a sour spot that sometimes occurs with the CAI that will vibrate the whole truck.

If it were not for the Banks Stinger System 48485 I would have gone with SCT for the tunes, K&N on the CAI, and Borla for the exhaust system.

 

As for me, truck is mostly stock but does have a leveling kit and slightly larger tires (they come out to about a 33"). I am very easy on the gas and squeak out good gas mileage from most of my vehicles, hence the shock for this one.

 

My truck's mostly stock and gets the worst gas mileage of all the vehicles I've ever owned except a 1975 Jeep Grand Wagoneer all wheel drive, all the time. Our Chevy Suburban does much better.
I got the leveling kit and slightly larger tires also but it was bad before that, too.

 

I get 13.5 in the winter 15 in the summer mixed driving. Has been the same way for 3 years now. Between letting the truck idle with the defrost on and the different blend of gasoline I am not surprised at the seasonal difference.

 

Ok, That was very helpful, Thanks alot for the info. I needed to know which one as being that I just installed the K&N CAI. Thanks again1