Losing Acceleration after 1/2 tank of gas

It's under a limited warranty through the dealer that I got it from, but not under warranty by VW. We are taking it Thursday to see if they can diagnose the issue, just didn't know if there was something we could lead them towards. We figured it had *something* to do with the fuel pump, but it only has 20k miles on it and the previous owner states he had no issues with the vehicle.

Just a guess here but maybe there is a gas tank venting issue that is not throwing a code. If the pump is trying to draw fuel against a vacuum it could cause the problem you have. When you open the gas cap does it suck air in?

Im guessing this would be an audible thing? Not that I have noticed but maybe I need to pay more attention? It is just over a half a tank at the moment. Should the car be on or off when I listen for it?

Clearly the less noise the easier to hear air being sucked into the tank.

I am going to try it later when I get off of work. Theoretically speaking, what if I do or do not hear it?

If you hear a sucking sound when the tank is low on gas there is a venting problem. The next step would be to check out the EVAP system.

Took it to VW in Columbus, Georgia after the Autonation dealership we bought it (and the extended warranty) from said they wouldn't touch it because its a VW and not a jeep/dodge/Ram. After inspecting the car, they duplicated the issue with no problem. Apparently there is a molded piece within the fuel tank that has become warped and overheats the fuel pump after the tank hits a 1/2 full. They also observed that there were lines inside the tank and outside of the tank that had rubbed and become sheared and damaged. Solution: a whole new fuel tank with fuel pump. Covered under the warranty and honored by VW