run a 2wd 4.2 v-6 reg cab short bed with nothing in it but the driver






sorry, but asking about gaining MPG in these trucks is pointless. You need to get your speedo set properly.

anything over 12-13 MPG and you shouldn't question it IMO. especially lifted with 35" tires


for you, the most economical thing would be to go to the dealer. Pay the $50-100 fee for the speedo reset and just drive normally.

 

I'm not sure you are clear here. The root problem is that your odometer is reading wrong. That's a big chunk of your mileage loss and it's on paper, not real. The actual loss is less. Step one is to correct your odometer. You can do that by having the dealer reflash your computer (if they will) or by getting a programmer that will allow you to reset the tire diameter in the computer.

Here's how you can get an odometer correction factor to calculate your actual MPG.

1) Drive your truck over a measured mile on a straight road (freeway mile markers are good) and record the distance your trip odometer shows. It's best if you do it over a few miles to makes sure you have a consistent number.

2) With bigger tires, your odometer will show less than one mile. For grins, let's say it was .9 (nine tenths).

3) Divide the .9 by 1 (.9/1=1.11)

4) When you fill up, multiply the distance on your trip odo by the 1.11. If the odo showed 250, then 250x1.11= 277.5 miles actually driven. Use 277.5 as your miles to divide by the gallons used.

5) Examples:

A) If you used 25 gallons and showed 250 miles, that's 10 mpg (250/25=10)

B) If you divide the 25 gallons into 277.5 miles, you will show 11.1 mpg (277.5/25=11.1)

In reality, you are off by about 13 percent so 9 mpg plus 13 percent is a bit over 10 mpg actual.

In my experience, not much you can bolt on will give you 3-4 mpg. Believe me, I have a fair bit invested in my truck trying to do that (see my Sig and there's more than it shows) and I can barely get 3 mpg over my stock baselines... and that's driving in perfect conditions and like an old man.

The best tools for mpg are a driver working in harmony with an instant fuel economy gauge (such as on the Edge programmer or a Scangage). If you stay focused on that monitor, you can get your mileage up 1-2 mpg at least, with no changes to the truck. Also, run your truck as light as possible and keep the speed down (aero forces eat fuel). A bed tonneau can offer a solid 1 mpg increase at freeway speeds, according to most tests (including some by the EPA). This is somewhat variable according to the truck's bed length.

Bottom line, it's like Tylus said. I don't agree it's POINTLESS but you can only get so much work out of a gallon of fuel. You could spend a lot of money to gain a coupla mpg and take a decade to pay those costs back in fuel savings. If the truck is eating you out of house & home, it's time for a Ford Focus or something economical but a lot of time, a trade-down like that is not economical either because you lose your *** on the truck. From my experience, your lift and tires are costing you 2 mpg, so you'll be forever adding those extra costs to the 4 grand you paid for the lift. You can probably gain that 2 mpg back, but it will cost you another 2 grand. A vicious circle.

Best Advice: Correct your odometer, drive easy when you can (that's FREE mpg) and enjoy your truck!

 

i am only getting 8.3 mpg right now not 15..ok so if i do the math that you told me i would still only be getting around 9..i know my truck is capable of more.. i looked at the edge programmer and it seems to me that it is just for towing and more of acceleration performance. Anything else i could use

 

I have a stock 2006 F150 4 wheel drive with the 3.73 gears and stock tires and get between 14 and 15 mpg. Adding a lift kit and larger tires will probable get you down to 10 or 11 mpg. If the tires and wheel combo are unduly heavy, subract from that. If the tread pattern is an aggressive mud terrain, subtact from that. If your truck's acceleration sucks because the engine isn't running in the correct RPM range and you drive it with your foot in it, subtract from that. These are all factors. How fare off was your speedometer? at what speed?

 

What size wheels/rims? 17?

 

I could write you a bood on lifts and large diameter tires, but unless you calibrate your tire size through the PCM, and get your gearing back in the stock range (i.e. if you had 3.55s upgrade to 4.10s or 4.56s) which also has to be calibrated in the PCM, your mileage is going to suck. Even after doing this, your mileage will never be back in the stock range. It takes a lot of effort to move the heavier tires and uses more power, not to mention the aerodynamic issues by having a higher stance. Regearing your truck is going to set you back quite a bit of money for the parts alone, and unless you're capable of doing the install, you might end up spending as much as $1,500 to $2,000. Getting someone to change the parameters in the PCM, probably adds another $500 for a tune and flash tool to write it to the PCM. I've run oversize tires on two broncos and regearing makes a lot difference in performance. Changing the PCM info, makes a difference in how the PCM interprets shifts, anti-lock braking sequences and other parameters makes for better drivability as well.

 

the speedometer is off around 5-6mph..which is a big difference. I have 35" tires and 17"rims.. i really dont have the money to change the gears, and not really interested in that.. the edge programming chip sounds mostly for towing and acceleration mainly..am i wrong? i am a begginer at this truck lingo and knowledge..thanks guys

 

Here's the bottom line: It will cost you another 2-3 grand in assorted products to get 2-3 more mpg.

The Edge unit will help with towing and acceleration but also fuel economy a little (about 1 mpg). Plus it will allow you to correct your speedometer so you can find out your true fuel economy. Best of all, it will will allow you to monitor fuel economy. I haven't researched any other programmers but I imagine there are other, perhaps some that are less expensive, that will allow you to correct the speedo. The Edge is between $400 and 500.

Putting this as simply as I can, if you do only one thing, get the speedo corrected. One of the important elements your fuel injection monitors is speed. If it's getting the wrong information, your engine is not operating properly and the transmission is not shifting correctly. That is costing you mileage over and above what the lift, tires and gearing mismatch are costing.

 

P255 70R17 (stock tires)l. I just did a road trip and got it to eek out 16.2 mpg keeping the speed for the most part below 70 mpg. Add a lift and wider, taller, heavier, more aggressive tires and I would expect highway mileage in the 13-14 range and city in the 11 mpg range. Ford, in their infinite wisdom of drinking the coolaide and believeing all anybody wants is power, hasn't done squat to improve mielage since my 1986 Bronco. But it's got gobs more power! I will say it looks like for 2009 they finally did something in the mileage department.

 

something is wrong with your truck or you were going alot faster than you'll admit.

my 06 Screw can pull down 20 mpg highway at 65-70 mph.
5.4 with 3.73 gears

 

Could also have to do with method to calculate MPGs...maybe he was using his message center's calculations?

Or another common one is to fill up your tank, and use your total tank's capacity to figure MPGs, instead of the actual amount needed to fill the tank...

But I have to agree, I see 20 MPGs on trips most of the time....

 

I have a 2005 Lariet 2x4 with stock everything and I get 14-15 mpg.

I have researched and I am now saving up the money to perform the following.
A. Tonnue cover over the back supposedly will add 1-2 mpgs
B. Cold Air Intake supposedly will add 2-4 MPGs
C. Flow Master 3" Dual exhuast supposedly will add 2-4 MPGs
D. The Edge Programmer not only will add power it will supposedly add a few MPGS also.

This stuff is not cheap but most you can do your self and save a little. I figured it would take me about 8-9 months if I get the desired increase to actually recoup my money in gas savings however I would be giving that much less to OPEC each month right.

 

Will certainly NOT add up like that! These manufacturers like to claim big figures, but trust me, you'd be lucky to see maybe 1 MPG difference with ALL of them combined.

People come here frequently trying to achieve the same goal as you, but they never see these lofty gains that are advertised on the website. If what you said were true, you'd see minimum 5 MPG difference with all of these, meaning you'd see 23-25 MPGs on the highway...which just doesn't happen.

 

First off reset the tire size in the pcm!!!!! Do that first! If the odometer is off so is the mileage calculation!

 

Thanks Tom, I did not realize that, I was hoping to try and get up to 20-21 but I quess if wanted the 5.4l I should just enjoy it and keep my foot out of it LOL.