Hi Chris, From what I have found --- on a Ford Forum --- is that P0251 is a generic code, and covers a multitude of issues surrounding glow plugs, injectors etc, or even a fuel leak somewhere along the fuel line. There was no mention of the fuel pump or leaking cylinders. It might be worth a second opinion. But I am not on engineer, just a former accountant, so I always Iook for the cheapest option. Regards, Peter.