1989 Ford F150 Dual Tank Problem

I have dual tanks on my F150. The truck has new gas tanks in the front and rear. The rear tank is reading empty while the front tank is reading beyond full. The truck stumbles and tries to die with the front tank engaged. The truck will run on the rear tank but spews gas out of the front tank gas cap constantly while driving. If you attempt to take the cap off the front tank, it will shoot out like a "shaken coke-a-cola".....any advice would be great...