So, I have a 21 FF RR SV Autobiography Dynamic Holyoke (I hope I don't have to type that out every time to identify the truck! ). The one consistent issue I've noticed is that for a 27.5 gallon gas tank, it seems to be relatively inaccurate in the amount I have to fill up with, once the low fuel light turns on. I have never put more than 20 gallons in it and always within 5 or so miles of the low fuel light turning on. I cannot believe there is 7.5 gallons in reserve. For example, just got back from about a 1,500 mile trip, averaged around 23 on the highway (straight highway) and when the low fuel light kicks on the most I can put in is around 20 gallons (give or take a few tenths), the display tells me I have around 50 miles of range left (which would be 2 gallons based on 23 mpg or so) but no way does the computer assume there are 7.5 gallons left. OEM everything with the vehicle. 22" wheels are stock and the tires are still original as well. When I calculate out the old fashioned way of miles on the tank versus gallons filled it's very accurate to that 23 average so yes, around 450-460 miles on the tank.

So my question is this, through an IID tool or otherwise, is there a way to correct this? What I'd like to do is throw a 5 gallon can in the back and drive until I run out of gas but yes I know the damage that can cause to the system so no, I won't do that. And yes, I've gone back to the dealer and they tell me it is operating "within spec".

TIA! 21 FF RR SV Autobiography Dynamic Holyoke Edition
21 Jeep Trackhawk
19 VW Golf R HPA Modified
12 BMW E93 M3
07 Mercedes S65
02 E46 M3 race car LS-X modified (720HP)
95 E36 M3 race car S54 modified (400HP)
04 VW R32 race car (600HP)
10 Buddy Blackjack

I think you have answered your own question....

What I'd like to do is throw a 5 gallon can in the back and drive until I run out of gas but yes I know the damage that can cause to the system so no, I won't do that.

They don't want anyone running out of fuel so I imagine that is why it is set up like that...

And I doubt it's adjustable, maybe email Gap and ask... Pete
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2014 L405 Autobiography SDV8 4.4 Loire Blue Ebony interior
2011 L322 Vogue SE 4.4 TDV8 Baltic Blue. Parchment over Navy Interior. Sold
2012 L322 Autobiography 5.0 Supercharged Ipanema Sand, Jet Interior. Sold
2002 L322 Vogue 4.4 V8 Epson Green, Ivory over Aspen Interior (Fatty Offroader) Sold
-Click for Project Fatty off roader-

Yeah, I hate the thought of introducing 5 other issues to solve one, but sometimes you just have to accept it for what it is. One day I'll probably be forced to test the limits, like I have before in the middle of nowhere and then I'll really know.  21 FF RR SV Autobiography Dynamic Holyoke Edition
21 Jeep Trackhawk
19 VW Golf R HPA Modified
12 BMW E93 M3
07 Mercedes S65
02 E46 M3 race car LS-X modified (720HP)
95 E36 M3 race car S54 modified (400HP)
04 VW R32 race car (600HP)
10 Buddy Blackjack