I have purchased a 2004 F150 SCrew. It has the 3v 5.4 L motor with the FX4 package.

The sticker on the window stated that I would get 14 city and 18 hwy. I have taken this vehicle in to the dealer many, many times and they tell me that the vehicle is getting 16 city and 20 hwy accourding to their WDS (I think that is the name of the machine).

I beg to differ. They tell me that by doing the old fashion calculations I am way off and they are not acceptable ways of computing mileage. I have taken the Miles driven and divided the gallons of fuel used.

I am consistantly getting 9-10 in the city and 12-13.06 on the highway. The dealer has said there is nothing wrong with my truck because their computer says what it says. There are NO error codes showing up either.

I find it hard to believe that we are 7+ mpg away from one another.

Does anyone have any suggestions?

I have heard to disconnect the battery, leave my lights on to drain out the pcm and then reconnect and go drive the truck to retrain it. This was a truck that had 380 miles when I bought it off of the lot.

Do I need a new PCM? I have had it reflashed supposedly.
What can I do to increase my fuel economy a little more since the dealer won't do anything because they believe me to be getting 16-20 and I'm no where close!

 

Hi Yellow,

Is this your first brand new vehicle, perhaps, or the first time in a good while, etc? I ask simply because it's been a pretty well known fact for years that the way automakers generally get those kinds of mpg numbers on the window sticker is in an *ideal* state of condition/configuration of the vehicle - and may even be with slightly different options on your exact same model. They check over *everything* to get those numbers - maximum tire inflation pressure, spot-on 4 wheel alignment, feeding it the very best fuels, driving it very precisely (and usually on flat ground at sea level), etc., etc. It's an *ideal* best-case scenario number in many cases, not any kind of average to be expected by everyone, no matter what - far from it.

I can't tell you if you are correctly calculating your fuel mileage, but I can tell you how to do it - the way to do this consistently and accurately is to fill up at the same place (preferably the same pump, too), and in the same manner - never topping it off, but instead, letting it stop when the pump clicks off automatically the first time. Then you take the number of miles driven since the last fill up, and divide that by the number of gallons required to refill the tank, and *that* is your correct number of miles per gallon.

Are you buying gas based on price, perhaps? If so, stop - that hurts mpg, and is among the worst things you can do to your vehicle's engine & fuel delivery system long-term. If you are doing that (buying gas based on price), start spending the money to use better quality fuels - it pays off in fuel mileage as well as in greatly reduced combustion chamber deposits, keeping the entire fuel delivery system clean, etc., and the longer you keep the vehicle the more important doing this from Day 1 becomes. Do NOT use any off-brand fuels, no-name fuels, and no Exxon/Mobil, either - they are lower energy fuels, and will deliver worse fuel mileage, generally speaking - even though some of them are "clean," like Exxon - a very clean fuel, generally speaking - it's just low in energy because it's "reformulated" year-round everywhere in America. I mention this because we find many people only looking at the cost per gallon, and buying their fuel based on that - wrong answer. The gas retailer isn't giving up his profit margin to give us cheaper gas, he's not taking food off of his family's table because he loves us so much - you pay less because the retailer paid less, for a "lesser" fuel - a lower number of BTU's per gallon (lower "energy content") the vast majority of the time, as well as fewer and not as good detergent additives, etc. (You can use the search feature here to retrieve previous posts of ours regarding which brands of fuels to generally use in various areas of the country.)

Which factory program is in the PCM is *not* your problem - you aren't going to be able to make Ford or any of their dealers make that motor run leaner than stoich A/F's (14.64:1) in closed loop, for example. Better mpg is NOT going to be attained by continuing to reflash the PCM with other stock factory programs, or by replacing the PCM - in your case, the mpg is everywhere else *but* the PCM, basically.

Start with getting everything on that vehicle as close to literally perfect as you can - tire inflation pressure checked every week, rotation & balance of the tires every 5000 miles (including at 0 miles!), the alignment, the fuel it's being fed, how it's being driven, etc. Make sure the tires are inflated to their maximum recommended level for sustained highway driving (whether you drive highway much or not), have the tires rotated and rebalanced every 5000 miles (and they aren't balanced well from the factory, especially the 18" units), make sure you get a sharp 4-wheel alignment done right now (that isn't spot-on from the factory very often, either), etc. All of those things (and more) affect fuel mileage and can be improved upon, especially on a brand new vehicle - starting with what fuel it's being fed, and then taking care of everything else.

Then once you've got it optimized, then see what your mpg numbers are. And if you still want more mpg, there are a number of performance modifications that will not only add power & performance, but also help mpg just as a by-product of their original purpose as a "performance" mod. Our 2004 was getting about the same mpg as yours, but now I can cruise at 85 mph and get 14.5-15.0 mpg - and if I just keep the cruise control on 65 at sea level, I can easily top 21 mpg, sometimes 23 at sea level & no wind, etc. "Normal" driving for us is tough for mpg, as we live in the mountains - not real high, but 1800-3500 ft. (and you lose 3% of your power for every 1000 ft. above sea level due to the thinner air, further hurting mpg), so we're always going up and down mountains, very little of our local driving is on flat terrain. And with all that, we now get anywhere from a low of about 15.0 to as much as 16.1 mpg in non-highway driving. We have improved our 2004's mpg by roughly 3 mpg from the performance mods - which aren't intended for mpg, but some will have that affect.

In short, I'd say your truck is doing exactly what it should be doing in it's present condition - so improve it's condition and what ti's being fed, starting with the items listed above, and you'll most likely see some better mpg, without doing any "mods" to it.

You've got a beautiful new 2004 F-150 there, a top of the line, very expensive & capable truck that many here would drool over - a loaded new 2004 5.4 FX4 SuperCrew. Just do all the normal required new vehicle sorting out, and enjoy that fantastic truck.

Good luck,