I've replaced a few fuel tanks on 202's and 208's( similar design ) to correct this problem. There's a flap at the bottom of the fuel neck that's supposed to open when re-fueling, but sometimes it doesn't open all the way. This causes the fuel nozzle at the filling station to shut off. The flap in question isn't accessible so there's no way of knowing for sure whether it's actually working or not. MB is aware of the problem, so it may be worth a call to your dealer to see if they can help. It's definitely noy a DIY job, as the rear sub-frame needs to be removed to replace the fuel tank. If I remember correctly, there may be a modified expansion tank/fuel neck available to correct this problem as well. I'm not sure, but I think this only applied to the 208's. Your dealer should be able to give you more information. Good luck, and let me know how it goes.