Low Fuel Light - what's in the tank?

[wanaride67]

I have a 2023 3.5L Ecoboost FX4 SuperCrew with 36 gal tank. On a couple of occasions I've gotten a low fuel light with message saying "you have 50 miles to empty". My average MPG is roughly 20mpg, so I presume the tank has about 2.5 gallons left at that point.

When I go to fuel up, I expect to put around 33.5 gallons into the truck (33.5 + 2.5 = 36). However, the tank only takes 29-ish gallons.

So this makes me think there is a 4 gal reserve, beyond the 2.5 gal for the "low fuel light".

Does this sound right?

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[StoneGray22]

That sounds about from what I remember the only time I let it get that low (I think my DTE was around 5 miles). Just checked my spreadsheet, the most I've ever gotten in at a fill up is 32.66 gallons.

 

[Aonarch]

It's between 4-6 gallons left. Don't run it past 0. The fuel remaining is to keep the fuel pump happy and prevent fuel cut outs at angles.

 

[gagliano7]

I ran mine recently to 50 miles to empty no light and it took just under 30 gallons.

 

[mredwin25]

Don't run it past 0. The fuel remaining is to keep the fuel pump happy and prevent fuel cut outs at angles.

This ? fuel also keeps the pump cool and prevents it from overheating, running low on gas will also stir up junk

 

[Borchelt]

and that junk will clog your injectors. Resist the effort to continue and fill it up around 1/4.

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