Can someone explain this to me

maybe the hose shut off early.

 

Head/tail winds ??
You can never rely on a single tank fill......or two even......to draw any valid conclusions about gas mileage.

 

This and too many other variables to consider. Maybe the car just likes that station's gas.

 

I think the station is somehow hacking into passing cars and triggering the low fuel indicators.

 

most of the power must be coming from the battery.

 

Winds can make a pretty significant impact. Many's the time when I've felt great about the excellent fuel economy I'm getting on a trip, only to have it completely reversed when making the return journey due to winds that are now working against me instead of for me.

 

I didn't want to get into any conspiracy theories, but it's a possibility as well...

 

The miles until empty bases its info on past tanks mpg. The gas light comes on exactly when that counter reaches zero. It takes a few tanks to change its counters.

There's around another whole gallon still in the tank at that point. Toyota really doesn't want you to empty the tank. Running on the very last drops of fuel is bad for the fuel pump, it'll cavitate and run dry, while sucking any debris left in the bottom of the tank. The fuel pump motor is actually cooled by the fuel it pumps, so it will overheat with no fuel. If you drive it until it actually runs out of fuel, the car will continue to drive as far as it can on electric only, to the point of draining the hybrid battery to nothing. After that the car will have to be towed to a dealer for an HV battery recharging.

 

I have to comment on several statements that conflict with my Liftback behavior:

When initially filled up, DTE is estimated based on past mpg. But as the tank empties, DTE does not count down exactly as the odometer counts up. Instead, it applies that recent MPG to the current fuel tank level. On steady level roads, it should fall to zero at the same level on the fuel tank (not empty, a significant safety margin is built in), barring drastic changes in fuel consumption.

Beware that hills do cause drastic changes. Uphill requires a lot more fuel, causing DTE to count down much faster. But downhill gliding without burning fuel does not fully make up for this, as DTE is forced to count down a minimum of 1 miles for every 2 miles added to the odometer. These effects can cause DTE to drop to zero prematurely. And if you add just one gallon that is not recognized as enough to reset the display, DTE will just continue dropping 1-for-2 miles until it either catches up, or reaches zero, whichever comes first.

Bob Wilson deliberately ran his two Prii out of fuel more than 50 times, for fun / sport / engineering curiousity and research, and had no fuel pump problems.

I'm not sure why debris on the bottom of the tank would wait until near fuel starvation before getting sucked into the intake. It isn't as if the intake moves higher depending on fuel level.

Gen2, maybe. Not Gen3. Here is how a Gen3 typically runs out of gas:
[WARNING] Running out of gas (Gen III) | PriusChat

 

Bob probably did not try to see how far he could force the car to go AFTER the fuel had run out.

And contamination/debris that is FLOATING won't come anywhere close to the pump inlet until the fuel level gets really low.

 

@fuzzy1...there has been some concern about monitoring TPMS as an invasion of privacy, but I do not think the station owner would do that

 

Reread the linked thread. He did end up doing so in those episodes.

But this was about running on the lowest fuel, not running beyond the point of no fuel.

When people talk about debris left in the bottom of the tank, I generally take that to mean the sinkers, not the floaters.

 

I can vouch that the car has ~1.5 gallons of gas left after the light comes on, but I tend to fill up ~50 miles after it does so. 80k miles on my car, so far, no issues. I'm averaging 9.28 Gal/fill-up on 170 fill-ups.

 

It is my experience that it is not about the speed you maintain but the method in which you maintain it. You will burn the same fuel at 65 as at 80 if your foot action is identical otherwise. I have driven to Vegas and back from farther than Los Angeles. I was astonished that the fuel burn was as good as it was but it was good because of methods I use locally. My average in 33k miles was 54 mpg. I still have not replaced my totaled 2015C3, but my methods also increased the average miles on a gas powered rental car. So my way of driving was to be very light and easy on the gas pedal. Even while accelerating to 80 mph, doing it without putting my foot fully down to maintain it. Get there rapidly and sacrifice efficiency before the speed is reached and then stay light and sparse to maintain. Keep light and sparse and the speed can be maintained. Learn the meaning of the Eco Score arch. Stay on the leftmost of it that you can.

 

The highlighted sentence is absolute baloney:

Updated MPG vs MPH chart | PriusChat

Steady State Speed vs Fuel Economy results

 

Agreed... you'll be lucky to get the same MPGs at 65 as you do at 75, let alone 80.

 

I think headwinds and tailwinds are messing with your mind...