This is my 2nd fill after my 1st tank, which I got 17.8 average on I estimated but that had a nice interstate drive on the tank. I just filled up a tad bit over a 1/4 of the tank and it came out to 8mpg. I'm driving my truck pretty normal. Never really past 1/2 throttle I can think of. This was all city driving too.

Should I expect this with my new truck or will it get better as I break the motor in more? My old truck use to get 14.5 even when I was driving it hard.

 

8mpg can’t be right unless you have a hole in the tank. Hopefully, you miscalculated. I average approximately 16mpg mixed driving; give it a chance, it’ll get pretty good mpg’s once it’s broke in.

Congrats on the new ride!

 

You need to start with a full tank for an accurate result. That's what the mileage numbers are based on. My XLT brand new was getting 14-15 MPG/city. After 18 months I average 16-17 MPG/city and about 20-22MPG/highway.

 

Yep. Can you tell me exactly how much a "tad bit more than 1/4 tank" is in gallons. To perform MPG calculations you can't guess. This has to be as close to a percise measurement as possible.

Here's what you can do:
1) Fill up your tank completely (you will need a second mortgage for this )
2) Get the printed receipt that has the amount in gallons that you pumped in.
3) Flip the receipt over and write down your current odometer reading on the back.
4) Keep the receipt in you vehicle till the next time that you fillup.

Now this is the important part:
6) After your second fillup get the new printed receipt and note the gallons it took to fillup this time. Get your previous receipt. Now subtract your initial mileage record from your current mileage. Then divide that value by the gallons that you just added. Viola, mpg.

The formula looks like this:
Mileage (Final) - Mileage ( Initial) = Mileage (Difference)

Then:
Mileage (Difference) / Gallons you just put in = Fuel economy.

Keep your reciepts for the next several fillups and do the same each time. After about 4 times then you can aveage all you data together and get an average mpg.

Hope this helps

Ox

 

I get about 13mpg city/hwy in the summer, and 14mpg in the winter.
05 SCrew 4x4 LARIAT.

Apparently AC is worth about 1 mpg.

These numbers come from the handy dandy trip computer, never actually did the math myself.

 

A lot.

Ox has some great points, so does your manual...

Use the same pump at the same station if possible, it's tough to determine gas mileage unless you top off at fillup.

Keep your receipts and note the mileage. I just use a little notebook to log all fluids. Don't worry about mpg until you get 1000 miles on it and everything seats in. You should see a significant improvement after 1000 miles.

(Keep an eye on your other fluid levels hot/cold and tire pressure until you get used to the levels, especially during break-in). Ford did a great job making checking fluids almost idiot-proof.

One thing I noticed on my 'o4 4.6L is my low fuel light kicks on when there is 5 gallons left in my 27 gal. fuel tank, with the gas guage needle square on "empty". Nice buffer, though I wouldn't depend on it.

I'd swear my truck was stuck on getting 10.5 mpg my first 1000 or so miles, no matter how I drove. Then the mpg took off to around 17/13 hwy/city. I'm still under 10k total miles and it seems to improve every tank.

My guess is my driving improves every nickel I see gas go up...

Good luck, -Ron

 

Ummm... I did fill it full. I think everyone misunderstood.

I had the 1st tank of gas... 17.8 mpg.

I fill it ALL THE WAY UP and used up a little more than a 1/4 of that tank and then filled it up again. That is what I used to calculate my mpg and I got 8mpg. There was no error... The only error there could be is if someone reset my trip meter but counting I'm the only one that has keys to the truck and drives it, I doubt it.

 

Thanks. I know how to check mpg. A tad bit more than a 1/4 tank of gas on my truck is 6 gallons. I got a small tank on this truck. It appears to only be 20 gallons where as my last truck had around a 26 gallon tank.

There was no guessing and I even used the same pump at the gas station to fill back up again. Like I said in my orignal post, 8mpg. This sucks.

 

Ok, some points posted each time we get a mileage thread.
Don't check mileage unless you are down about third to a half tank. Readings are suspect, due to gas expansion, uneven filling, etc.

Don't Don't Don't top up this tank. Three clicks maximum from first click off. I've found that two or even one every single time is best. Just do it the same way each time.

If possible, fill at the same station, same pump, for maximum accuracy. They shut off at different points. Changing the nozzle, something a station might do on each pump two-six times a year will change its pressure release point.

Don't top up the tank. The tanks are wide and low, and if you top them too much, you can keep putting in a LOT of gas after it shuts off. It's not supposed to take that gas, and when the gas expands (air temp is higher than underground temp) it can do everything from rupture the tank, to force liquid fuel down your return and vapor lines.

Around town miles per gallon are not good on these trucks.
Freeway is not good when the truck is new.

My first 100 mile freeway jaunt with my truck delivered 15 mpg. Ouch. If I drove the same route today, at the same speeds, I would expect to get 22.
That's at about 7k miles.
I have modded my truck, but some stockers are getting close to the same mileage.

Did I mention, don't top up the tank?
Learn to drive the truck for better mileage, after it breaks in, and after the PCM learns your driving habits.
You can get two more miles per gallon at the same speeds, by learning how to take your foot off the gas earlier. This truck freewheels, or coasts unlike almost anything else you may drive.
That means if you take your foot off the gas five hundred feet from the stop sign, you will get there as quickly as if you don't. Check it out. That also will help the brake dust thing.
Get a Scangauge or something to show you how to save gas on this truck.
It's a new way of driving. I've owned many, many cars trucks, etc. over thirty five years of driving. This is a little different.
I like it, but it took a couple months to learn new habits.

Mods like open exhaust, tonneau, K&N seem to help most of the drivers. But just learning the peculiarities of this truck helps the most.

They do break in, they do run better.
If you stay down below 12 doing any or most of this, then there is a problem with the truck.
Good luck
Chris

 

You should run out more than 1/4 tank for a more accurate measurement. I'd run it down to as near empty as you're comfortable with. Also, your original post was a bit vague so I can understand why everyone misunderstood what you meant.

 

my truck is one of the ones on here that gets pretty bad gas mileage. but the only time I have even got close to 8 mpg was with heavy towing. I think either something is wrong with your truck or your trip meter reset its self. I always use my odometer not my trip meter. try this it might be differant. if you continue to get 8 mpg I would see the dealer.

 

I usually do but with the possibility of a Hurricane I wanted the tank topped off.

I'll see where it goes and start reading off the odometer. I'll give it till 1000 miles until I really start to get upset. I didn't get a used lightning because I didn't want 12mpg city 15mpg interstate like a friend of mine gets... I'm going to be pissed if I get that or worse with this truck. Plus, I'd like to supercharge in the future (2 or 3 years. Should have the $ after I take a few research positions) but if I'm getting 12mpg NA, then I dont' want to see my boosted mpg.

 

Relax, you have a 26 gal. tank. Run a few tanks through and you'll be fine, we all get goofy readings in the beginning.

-And best of luck against the hurricane.

Ron

 

Yeah, you're right. I just checked. It's odd b/c my guage was just a fraction above the E and it only took 15 gallons to fill up.

 

Really????

How can you explain a 123% decrease in your fuel economy between your fillups?

If you have a 26 gallon tank then a true 1/4 will be 6.5 gallons. That 1/2 gallon has to account for something. For someone in the research field you are pretty sloppy with your calculations. Stop using your fuel gauge to calculate your mpg and start using the actual amount of fuel that you pump into your tank.

Its threads like this that might sway a "would be F150 buyer" to buy something else. Before I bought my truck, I lurked here for about 5 months reading all of the threads, especially those that dealt with power, fuel economy, suspension, etc.

If I had listened to all the naysayers I would have missed out on one of the best vehicles that I have ever owned.