0559 FUEL RAIL PREASURE FAULT CODE LOOSES POWER

[CASPER1968]

I HAVE A 2009 FREIGHT LINER ISB 6.7 FAULT CODE 0559 IVE REPLACED THE SENSOR ON THE FUEL PUMP IVE REPLACE INJECTORS. PREASURE SENSOR ON RAIL. BUT I STILL HAVE THE SAME FAULT CODE THE FAULT CODE COUNT IS AT 1776 CHECK ENGINE LIGHT GOES ON OFF ON OFF ALL THE TIME MOREW SO AT HIGHER RPM" IVE SPENT OVER 6,000 DOLLARS AND COUNTLESS HOURS TRYING TO REPAIR THIS PROBLEM IF ANYONE HAS ANY IDEAS I WOULD BE SO GRATEFUL. THANK YOU IN ADVANCE.