2015 lariat fx4/Sport 502A window sticker says 36 gallon fuel tank...I average 15mpg, DTE always says somewhere around 490 when I fill up...do the math and that seems to be a 33 gallon tank, not a 36. Am I missing something?

 

run it below 0 miles to empty and see how many gallons it takes.

 

Clear your avg and see what it says. They dont have a 33 gal tank.

 

You would have to run out of gas then fill up. Even a 0 MTE there is still gas in the tank.

 

Yeah the miles to empty is more so you fill up before running completely out of gas

 

DTE/MTE isn’t a concrete number/calculation. Those numbers have some fudge factor built in. Grab you a 5 gallon jug of gas if you want to get a better idea of how accurate it is. Running out of fuel on a regular basis, or always running it very low, is supposed to be tough on the fuel pump. Oddly, I almost always ran my vehicle down very low on DTE/MTE and never had a fuel pump issue in the 130K+ Mike’s I owned it...but YMMV.

 

I've run it down to 30 miles to empty and screen showed I used only 30 gallons...15mpg would mean I only had 2 more gallons left...is it odd that when I fill up in has never gone above 493dte?

 

No not really. I see you are in NJ the stop and go driving the sudden stops and fast take offs all affect the calculation. I have seen mine as high as 699 miles and as low as 490 (when I was in Tarrytown NY). I don't worry about it I always fill up about a quarter tank. In the winter more like 3/8th a tank.

 

the computer calculations are all estimates... they are ballpark.
Figure the exact mileage by hand and go from there. Fill up before the tank hits E and you'll have no issues.

 

gauge/calculations will never let you use 100% of the gas in the tank. The fuel pump uses the fuel in the tank for cooling, if you run it to fumes you will just burn up the pump.