Help I have a 94 f-150 and for some reason my front tank when full will build up pressure that it will start to leak out of the filler tube. As soon as I take cap off it quits. It has now done this to me 4 times and leaks on garage floor. Has anyone experienced this problem before I am the originall owner of this truck and it has 60,000 miles on it just started doing this last fall. I dont believe that I am bringing any fuel in from the rear tank either????