They treated my buddy very well when his 7.3 was down. And I believe that your "injector knock" is called cackle common to 7.3 due to the design air enters the fuel system at the tank. (As far as I know F@rd says its "normal",just like the oil weeping from intercooler tubes) Just my $.02 and like I said they did a Great job fixing my buddies 7.3?