I’m kind of new to the diesel world . My 2006 lbz seems to run different on different days . Some days it’s amazing , others I have this damn knocking noise under any type of acceleration . This leads me to believe it’s fuel related . Am I wrong ? When knocking , I’m not sure if it’s a mental thing , but I swear it rides like a dog . Really sluggish . I have checked my balance rates and they’re all within 4.0 at a warm idle . The fuel rail pressure at warm idle is 4.3-4.4kpsi . When cold tho and I check the balance rates, there is always a random one that is a little high, like 5.0 . And the frp is 6.2. Is this all normal ?