Recently my 2006 Pacifica Touring has developed a very annoying habit. When I fill the gas tank on my car and set the pump handle to automatically shut off, it will frequently shut off before the tank is full. Occasionally it "belches" a bit of fuel out of the filler tube. I invariably end up having to go back and reposition the pump two or three more times before the tank will fill completely. I bought my Pacifica in June and have not had this problem until about the last month or so. I think this might be a venting problem with the fuel tank. Has anyone else had this problem and if so, what's the solution?