Sean, PM replied to...

As for this complaint, here is what helps us GREATLY when we diagnose this problem. We need to know if your tank is really only getting 3/4 full, or if the gauge is giving inaccurate readings(which would be the fuel senders mentioned above). Try running the car fairly low on fuel, then do a fill-up. Pay attention to how many gallons your car accepts via the fuelpump readout- does it get to 20 gallons?

The reason we need to know this is that we have seen to different situations that can cause this concern. The first is the fuel sending units- there are 2 in the tank- which give the fuel gauge its signal and the other is actually the fuel tank itself. The fuel tanks in ALL recent vehicles, with all car makes if I recall correctly, are equipped with a Fuel Vapor Recovery System designed to keep vapors from escaping into the atmosphere. This is accomplished via a flap in the tank and a charcoal canister. If the flap in the tank gets bound, it can prevent a full fill.

Hopefully, this sheds some light on this...

 

thanks John....

mine WAS the later....and it was always at exactly 1/2 tank....

as for Sean's story, if he doesnt mind me telling it
He was running on fumes, it seemed, as the gas light was on and all. Then we stopped to 'fillerup' and it only held i think like 14gallons and i tryed my tricks and got another gallon or so but then it started overflowing. We cleaned the gas off the car and it still read about 7/8....

 

Just wanted to update everyone. The dealer has decided to replace the gas tank. Suppost to get the car back tomorrow afternoon. I will let you know if it fixes the problem.

Also i got the 2005 sedan as a loander, sweet car.