Just got a 2003 F250 5.4L crew cab with 102000 miles on it. I got the truck for my tent rental business that i started! Have been looking in to a few different ways of improving gas MPG. Was curious if anyone had any ideas. I know i am not going to get a big gain but am looking for anything I can get. Should I get a programmer? If s what one. Cold air intake? If so what one!

 

Stock air filter is better than any aftermarket air filter. if you bought a Super Duty with the intent of getting better mileage, you may want to forget about that. Although that's a gasser. I'm a diesel kind of engine guy. Not made for better MPG, it's made to work. FYI Welcome to FTE. You may want to mosey over to the 5.4L section, here: Modular V8 (4.6L, 5.4L) - Ford Truck Enthusiasts Forums

 

All engines come with a weak spot from the factory. The 5.4's Achilles' heel is its exhaust. I have seen bills pass through congress better than exhaust through this system.

Start at the manifolds and work your way back. First just look for problems; mainly rusted pipes, leaks, etc. Then decided how much you want to invest, then realize that you most likely will not ever get a full return on that investment. A full exhaust system would be comprised of new shorty headers (mid- and long-tube headers dont fit), a new Y-Pipe, and a cat back exhaust. This is of course assuming you want to keep the cat to me legal. The biggest improvement for single upgrade will be had with an SDP Y-pipe. After this will be headers, then the cat back system. So choose which of these if not all you want to do and then have at it.

Of course this is just one mans opinion, and there are many other things to look at, too. Tuners are great and can help boost overall mileage over a long period of time such as a year. However you most likely wont notice a day-to-day mileage increase. This is how mine is. Day to day I dont notice huge increases of mileage, but since adding the tuner I have gone from a monthly average of 11-13MPG to 13-15MPG. (I do not have a 5.4, I have a 7.3. I'm just giving an example here.)

Best of luck and welcome to FTE.

 

^ what he said. dont waste your money with a cold air intake, "throttle body spacers", or off the shelf tuners with canned tunes. if you want to tune your truck, then mike @ 5 star is highly spoken of around here for gas engines. dont expect much of an mpg increase though, i get better mpg in 87 performance tune than 87 economy. and even then, its hardly noticeable. if i get over 11 mpg im happy

 

Yeah..what he said. I totally gutted the cat and went with a glass pack and dual pipes
then put in a K&N filter in the stock housing, drilled a couple extra holes in the plastic housing just to let a little more air in and I did gain 2mpg so I'm up to 13-14 mountain driving and 14-15 highway so.....it's up to you.
I'm up to 134,000 on it now and still no codes after cleaning out the cat. ( no emissions where I'm at )

 

The best way to improve mileage is also the least expensive choice. Accelerate slower. Drive like there is an egg between your right foot and the go pedal. That will save you more gas than any hardware you can buy.

 

And Welcome to FTE, navcruit.

 

What mark said. And ill add....
Filters, fluids and air pressure in the tires. Get some low rolling resistance tires and preferably stock sized. That is your best bet. You could invest in a exhaust, tuner and a whole bunch of other performance items claiming high gains. They also cost a good chunk of money. Its a work truck not a toy or a project. You only likely to see at best 2mpg increase with all the bolt on stuff. If you tow a lot with the truck a lower set of rear axle gears also would help depending on what you have now and plan to do.