OK, a couple things just to add to this,
1.) As we might know, electric fuel pumps in the tank cell itself have pretty much been the standard for most vehicles for the past few decades. Electric fuel pumps need fuel to keep them cool, as in the pump itself needs to be submerged in fuel. In theory low fuel levels are detrimental for electric fuel pumps for two reasons. For one, the lack of fuel as a “coolant” if you will, will cause the pump to get hotter than normal. For two when fuel is VERY low the pump is now sucking in junk and debris that normally would probably not find its way into your fuel system otherwise. For those of us not fortunate enough to top off the tank to full twice a week, we live with the guilty conscious of knowing we are possibly causing premature damage to our fuel systems (ie: the pump itself, but possibly other components too). It is what it is. *IF* you can, always keep the tank as full as possible, preferably above 1/2 tank. I understand that this isn’t always practical for most people.
2.) I agree with the aforementioned posts that it’s probably not a good idea to take the display readout of how many miles to empty as gospel.
That being said, I’ve never heard of such high mileage estimations given by the computer while actually having basically empty tank as I’ve read in this thread. I’m wondering if this isn’t a GM thing.
I had an F250 that was issued to me as a company vehicle. I was the original driver of it since new. One day I had to make a 400+ mile round trip, I filled the truck up to completely full before getting on the interstate. I kept the truck in eCo mode for the majority of the trip. A/C on full blast the whole time, maybe about 10 mph over the speed limit for most of the trip. I was keeping my eye on the miles to empty display and it had gotten down to 10 miles to empty by the time I made it back to the city limits. I ran into some rush hour traffic and even though the gas station was only a mile and a half away, by the time I made it, the display read 2 miles until empty. I was impressed I managed to make it and thankfully never ran out of fuel.
With my newly acquired 2018 PPV, on the road trip back home the needle was getting very low. We were in a gas station desert and literally within seconds of the gas pump light coming on, an exit sign appeared for gas stations coming up. I’m glad I didn’t see this thread beforehand, because I probably would have been extra paranoid about running out of gas !
Anyways.. You can always just average out your typical MPG x fuel tank capacity to have a secondary idea of how much longer you can actually go regardless of what the display says. For example if you average 15 MPG, and have a 26 gallon tank, then a typical range would be 390 miles. 15 x 26 = 390. Of course that’s not entirely accurate either with many variables on the MPG side, but gives you a general idea.