MPG

OP where do you live? hills, mountains, altitude also have effects into the equation.

 

when you fill up has the truck run out of fuel? How much did you actually pump in the truck?

 

Motor isnt even broke in yet

Give it some time, light on the foot, and switch to synthetics

 

When the guage says E you haven't used 21gals of fuel. On E you have 3.5gals left in the tank, there is multiple threads on this. So you really need to divide miles you have driven buy the gals you put in and not just blindly divide by 21gals. 260mi / 17.5gals is closer to 15mpg. Not great but closer to what you are actually getting.

 

Your math is wrong. in these trucks, and most vehicles in general, the tank is not empty when you hit Empty on the gauge. there is a small reserve of gas designed to allow you to run the tank gauge to e and still make it to the next gas station. In our trucks in particular, the reserve is about 3-4 gallons. this being said, for an accurate MPG assessment, you need to take the distance measured on your trip gauge and divide that by the EXACT number shown on the gas pump when you fill up.

Example
Trip a distance reads 350
Gallons on the gas pump read 17.5

350/17.5= 20MPG

 

When my gas light comes on I am usually only at about 17.5-18 gallons. I have never had to put more than 19 gallons in my truck even after driving with the light on for awhile. If you are dividing your mileage by 21 you are most likely miscalculating, unless you actually are putting in 21 gallons at the pump. But that would surprise me.

 

But you are not driving until you run out before refueling. The pump tells you how much you actually burned. If you refuel with 1/4 tank remaining, you only burned about 15 gallons, and you got 17 mpg for your 260 miles. If you refuel at 'E,' you still have a gallon or two in the tank and you did not burn 21.1 gallons to drive 260 miles.

To try it a different way, fill up and reset. Keep driving until you run completely out. How far did you go?

ETA LOL got a phone call before hitting Submit, and several people made the same point.

 

OP, mpg is "miles per gallon". Take the miles your drove between fuel-ups and divide by gallons you pumped (not the tank size of 21.1).

Or just sign up at www.fuelly.com so you can get accurate mpg. I don't even both with Trip, I use the odometer and subtracts from the prior fuel-up to get my trip's mileage.

 

You HAVE to divide by what you put back in not the capacity of the tank. I have never but more than 18.5 in mine.

 

Agreed. Don't go by the low fuel light either (you still have 4 gallons when that comes on). I stupidly thought I was getting super low MPGs too until I actually started caculating it. 21.5 highway, good enough for me!

 

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Wow lots of responses, lots of good points.

Yall are correct, I run the tank from full to below E which gives me 260 miles to tank, I divide that by 21 gallons which gives me 12+

so according to your info I am at about where Im supposed to be. I bet if I swap out tires for some all seasons instead of off roads, ill gain a few mpg, and more when I go to synthetic.

you answered my question, thanks everyone!

 

You should only run it to the low fuel light.
There is many reason to do that.

 

WRONG.

I bet you don't pump 21 gals in your tank because if that is the case then you should be stranded (may be the pump cheated you...)

I average 20-21 mpg on 50/50 driving. Just pumped today 16.663 gals @ $3.239/gal for 339 miles.

 

dont run her so low, its not good at all.

FWIW I am around 320 miles before the light comes on

 

You should be dividing by how many gallons you put in to your tank when you filled up. Not the capacity of your tank which will give you lower values.

 

It's a truck, not a Prius.

 

All the really good explanations and he still thinks E means he used 21gallons....

 

X2. Let the truck get broken in. No wonder its so low. I went through the same thing with the last new truck I bought.

 

smiles per gallon Yes?