As with all my vehicles, I always want to know where the bottom of the fuel tank really is; I eventually do a "run dry" to find out, it seems. But today was my closest without taking it all the way: basically straight "E" on the gas gauge, and 22 miles of range displayed. The manual lists a 23 gallon capacity. It took 18.62 gallons based on my standard technique for ballpark fill consisitency when calcualting MPG (autofill at max flow until it trips off, pause, then hand fill at 1/2 handle till the first click off, and it's done). Is the 23 gallons a literal tank capacity, or a useable figure? With a possible 4 gallon or so reserve at zero range on the display, a comfortable safety margin would exist. Although I am only getting about 1 mpg less than the LS 430, I feel the fill-up urge much more often due to the psychological impact of getting to low indicated fuel levels way faster. Only draw back to the GX so far! Anybody taken their GX down to the low fuel zone that Krammer did with the Saab on Seinfeld?

 

I have gone down to the Wire....that is the 'E' it beyond and the warning GAS PUMP light on the cluster. This went for 9 miles and that's it, I could not take more risk, as choking or starving the Engine without fuel is bad !! Repercussion are heavy on the Engine.

Now coming to what you mentioned as per the Manufacturer capacity 23 Gallon, there are two parts to this figure, First is the Usable Volume and Un-usable volume. The unusable volume is the portion of the fuel tank's liquid capacity that lies at the bottom of the tank out of reach of the fuel pump. The usable volume is the portion of the fuel tank's liquid capacity that can be delivered through the filler pipe into the tank when the vehicle is level (and when the unusable volume is also in the tank). And I think the manufacturer calculates the vehicle's fuel tank capacity includes the vapor head-space (that portion of the tank compartment at a level above the filler pipe neck) or the volume of the filler pipe.

I have gone to 19.5 max at the click, when the tank was made complete empty when the fuel filter was changed.

 

I'm suffering from the same thing. Tonight the gauge is on E. The computer shows 27 mile range (based on my 15 mpg current average). The low fuel light still was not on. I filled it up as much as I could and I could only squeeze in exactly 16 gallons. Once it's on full, it only takes about 20 miles before it's below the F mark. I'm wondering if there's something wrong with the sending unit.

 

While I can understand the desire to know where "zero" truly is on the fuel gauge, I seldom let it get below the 1/4 tank mark before filling up again. It's just a weird thing of mine.

Anyone ever notice the GX settles on the bump stops when going over speed bumps harder when the tank is closer to empty? For some reason mine doesn't settle on the bump stops (bottoming-out sensation) when full - just when close to empty.

 

I did notice that the car seems to require more frequent fill ups than the RX, but I haven’t gone the dry road yet on the GX. However I did run dry on the RX two lights before the GAS bar. Good thing that the lights were green and I was doing a clip and a half when the motor flamed out. The speed gave me just enough momentum to roll in to the gas station. Previous time I wasn’t that lucky. The car stalled a mile away. Lesson learned, I should stop driving my wifes’ cars. That said, the needle was almost hitting the rest support . Sorry if off topic.

 

I always maintain my fuel tank 1/4 or above, told to do so by my trusted mechanic for fuel pump's sake.