And no it's not because I have a happy tank! I have a 2005 mini cooper. This started a couple of months ago, but it has gotten worst in the past couple of weeks. When I pump gas, there seems that to much pressure is building up, tank starts to whistle and the gas pump stops. At first, the pump would stop every 5 gallons. however, now it stops at mid gallon, now apply that to 12 gallons and you see where it starts to get annoying. I think it has to do with the vent tube, but I don't know where it's located. I also search this site and the internet, but I only get results for battery vent tubes, so please help NAM!

 

It is the company whistling a very happy tune for the obscene profits they make on each gallon sold.

If not that you are probably on the right track about a vent being clogged. Your 2005 may have A rubber vent tube that the Alcohol in the gas turned very soft and it may be collapsed.

I sure hope someone here can help you and I hope it is not something that will cause you to have to remove the fuel tank.