What is the most common cause for hp pump failure on these 6.4l,this one quit on road and had #2 injector stuck open and badly over fueled that cylinder, after replacing that injector it ran for about 40miles and started running very rough, 4 cylinder missing and barely running.checked secondary fuel bowl and found shinny metal particals,called hotline and advise me to replaced all fuel component due to hp pump failure.Replaced pump, injector ,lines, filters and so on, truck runs fine and on road for over a month.Now we have a charge back telling me it is cause by fuel contamination , they found evidents of rust in pump when they took it apart.I never inspected the pump internaly and no shop manual says so, customer had fuel filters replaced and no water in fuel light ever come on (does prove out). Any hints how to convince them. PS very interesting web site Keith keep on the good work. Sorry about my writing, i,m french(not my fault HA! HA!).