fuel gauge or?
 

One of the boxsters I have never goes to empty on the gauge but runs out of gas at 1/4 tank. I believe the tank to be reading correct because I can only put 10-11 gals in when empty.

Any insight?

No way, something's off there. The Boxster has about a 16-17 gallon tank, so if you were bone dry you'd be filling up with close to that much...strange that the car is dying with seemingly 1/4 tank still in it.

I know my gauge can be a little funky at times, and when I first got the car it would not read full even when the tank was full...it would settle at around the 7/8 mark. When I picked up the car there was little fuel in it, and I think the float got used to being at that low position for a long time, maybe some corrosion even built up on the parts that were not sitting in fuel. Eventually this stopped and now it shows around that mark on a fillup and slowly moves to full as I drive away, then starts working its way back down. I guess the float is showing its age, but it still works, and I can drive right down to my low fuel warning light and still be running, not that I make a habit of it.

Your situation sounds really strange, though. I can't really imagine why the car would stop running with fuel left in the tank, or if it really is empty, why it would not take in enough fuel to its full capacity...something, be it mechanical or electronic, has to be tricking the car into thinking it does or does not have fuel when the opposite is the case.

Sorry I can't do more than speculate here, but I've never heard of something like this before.

Yeah the way the car is reacting, it is almost like the bottom 1/4 tank was filled with rocks or something. Is soon as the tank hits 1/4 the car runs funny and dies. :confused:

I wonder if it is possible the pick up is not at the bottom of the tank.

If you can only put 11 gallons when empty ...
 

... then the fuel pump was probably dislodged from its base and is "floating".
You'll have to access the tank, which is under the battery.
Happy Boxstering,
Pedro

That's was along the lines of what I was thinking. Because it is not on the florr of the tank the pickup is not either.

I feel the same as Pedro having changed one myself. The pump has to go in as directed and the fuel lines have to be routed properly. You must pay attention when replacing the fuel pump. Throw your cell phone in the trash can. Do it yourself, alone. Save the beer until you hear the engine start !!! No distractions.