I got my truck about 2 weeks ago, and have just passed the 1000 mile Mark. I took it on a 100 Mile each way road trip, on the way there I averaged 18.5 mpg, not amazing but I was ok with it. On the way home I reset the meter and got 21.3. I liked that, figured maybe it was calibrating better .

A few days after I went for a 200 mile drive and averaged 17.5. This is all basically on cruise set to 70, and yes I get the gauges are a bit generous, but what's up with the 4 mpg difference under similar driving conditions? Has anyone else come across this?

 

Windage, different blends of gas, terrain, anything, nothing, everything, etc.

 

^^^This. Look at a geological terrain map of your area traveled. There was most likely the maiden trip going up a grade more so that the return voyage. Wind always hurts these bricks, and unless you filled up after 100 miles, you had less gas in the tank for the return trip. Besides, a 200 mile trip is hard indicative of accurate gas mileage.

 

another issue is the ethanol concentration in the gas.
Our trucks at least from 2016 and up with flex fuel , you can read the ethanol concentration in the tank with Torque Pro.
Good tier 1 gas from say Chevron or Exxon will be roughly 9.8% ethanol.
Valero and unbranded stations is pot luck. I have filled up at a Valero and ended up with 74% Ethanol from a pump that is labeled less than 10% ethanol.
That particular station doesnt even sell E85. That means they got the wrong gas from the Distributor.
BTW the higher the Ethanol the lower mpgs go. That tank of 74% I got 11MPG hwy with a tailwind.
That said I average about 20 HWY 17 city with good gas. sometimes better sometimes worse but mostly it depends on the Ethanol content.

 

You won't start seeing real good mpg until you have at least 5,000 miles or more.

With my 2016, I get around 21-22 mpg on express with my Screw 4WD 5.0L w/3.73 axle and around 18.5 - 19.0 with mixed driving. Never seen below 16 with town driving.

BTW, in Chicago/NW indiana area, we are stuck with emission friendly 90% gas/10% ethanol mix here. You won't find 100% gas until you get far far away.

 

Thanks for all the replies, was same fuel for all trips, so I guess I'll chalk it up to just the elevation change during the drives .

Same setup as me,gives me hope!

 

22000 miles and never been above 17.6 mpg with 3.55

 

1400 miles and never above 9.8 hwy.

 

9.8 highway? What speed, 100? Something is wrong with your truck.

 

9.8 hwy doing 55 to 65. 2017 supercab 5.0 6 speed 4x4. Took into the dealer and guess what they told me "that is normal". And I only have the 23 gallon gas tank. It sucks taking it to the gas station to fill it up every 200 miles.