truck was purchased from a dealer stating it needed a turbo. after further investigation i found the turbo not to be the issue. the said dealership had just done a fuel system and cleaned the system(so they said). all components engine side are new. truck has high fuel pressure at idle 7,500 psi and smokes alot. first i removed injectors, had them tested and they said two were bad the rest were good. replaced the two that were bad put back in the truck dropped fuel tank recleaned and replaced fuel filter again because there was still metal in the fuel filter, after all that and I'm still having the same issue. so i then replaced the HPFP and the driver side rail, same thing however it is a little better. after initial replacement this time truck ran great for 15 minutes(normal fuel pressure at idle) then all of a sudden it started again it will jump up to 7,200psi then back down to around 4,500 psi. i can hear a thumping noise in the return line. so i removed the return line at the driver side rail and pushed a hose on the rail and ran it into a bucket and fired the truck up and its still thumping every time it thumps it pushes out a small amount of fuel, has anyone ever had a similar issue? i cant find anything online. thanks in advance for any help!