I am about to lose my mind. Here's the story. I have an 02' Boxster S. I fill the tank, and it gets completely full... of course, only after manipulating the stupid pump handle to get the tank full as it shuts off every 2 to 3 gallons.... but I digress. I drive the car thereafter, and it runs perfect! Until.... just below 3/4 tank... should be approximately 4 gallons remaining. And then the car acts like it has freakin' water in the gas.... it quits, or stumbles, and shuts off for a moment, only to catch again... I though...ahhhh, I got water in my gas. So I put some fuel treatment into the tank that is the anti freeze/remove H2O from you tank stuff... I've used this in the past on various hoopties I've owned in the poorer days.... haha. I ran a couple tanks this way, being sure not to get below 3/4 tank.... and today was the day off to experiment by driving below 3/4 tank between to strategically located gas stations. Oh, I forgot to mention that when this crap happens... just a single gallon of gas, and the car runs like new again.... anyway... today, at just a tad under the 3/4 tank level... the car freakin' died, and absolutely would not restart until I put 2 gallons of gas into the tank... than like new again. I called someone that has worked on my car before... too far to drive at this point to be practical.... and he suggested maybe the fuel filter was clogged or the fuel pump was on the way out. I just finished searching every Boxster forum I could find, and the impending signs of fuel pump failure are nothing like this at all... But putting in a fuel additive does nothing! HELP!!!! I'm going to sit here and drink Sam Adams Cherry Wheat until someone replies! I'm going nutz! Thanks in advance.