Metal tank, went to dealer to inspect. Truck has 65,000 miles, kept in doors. Rust inside of tank, 40 gallon between the frame, rear of truck. Rust thru out the fuel system. Fuel bowl full of rust. Ford seems to know about the problem. We took vehicle in for power loss at highway speeds (injector failure how everybody describes) instead they found rust. Makes you wonder how many other people have this problem.