G
Guest2017
Interesting this post comes the day after car and driver reported that their Mazda CX-9 long term car ran out of fuel when the gauge first went to zero and second when it was at 6 miles till empty. You appear to be seeing the same thing.
Me, I would add gas much sooner and call it a day.
I've confirmed at least a 21 gallon (US) total capacity on my 2018 Sig. They list it as having 19.5. I've pumped 21 one time thus far. I don't intend to do that again as I don't want to overflow and cause an EVAP canister problem with the charcoal down the road. The digital needle was one half-width topside of the letter "E". So, it looked something like this only slightly more empty than this similar pic:
From a little lower than this relative "empty" needle position, I was then able to pump 21 gallons US at something like $69 and some change. If he's running out of fuel anywhere above that level, he's probably got a problem that needs to be addressed.