High temperatures and certain driving conditions could cause the fuel tank ventilation valve to fail to fully close, which could allow fuel to leak into the fuel tank venting system. The fuel may even find its way into the evaporative system, saturating the carbon canister. If this occurs while driving, the car may have performance issues, like vehicle jerking. Also, a fuel leak needs only an ignition source to cause a fire.
Dealers will replace the fuel tank ventilation valve with a new valve for free. Owners can contact Volkswagen at 800-822-8987, or the NHTSA Vehicle Safety hotline at 888-327-4236.