I have the same issue as all above. Reason we have this problem is tied in mostly to the design of the fuel cell/tank. Being a multi-layer plactic contraption you have a few factors to set in. Flex, these are tanks with little as a 3mm inside wall thruout the whole assembly. Then, permination. Plastic soaks up gasoline after so long. So to help with that they apply a resin polymer for the " barrier" between the gas and the rest of the tank.
