I have a similar problem. Fuel was going from my rear tank to my front. I eliminated the front tank and joined the two lines together with a short hose.(saw that somewhere online) Truck ran great for a week or two. Then it started sounding it like it was running out of gas. Spitting and sputtering. It would shut off then would start up again, then go a little and shut off. Now i cant get it running at all. On a another note the rear tank would not take gas and its not ful, but there is gas in it. I would try to fill it and it would just blow back out at me. I dont no what to think. Any help would be great.