6 months ago i bought this 99 f250 sd from a auction , 5.4 gas, bla ,bla, bla ,
it has a strong knocking sound so i'am trying to see if it a valve hitting the piston or a rod knock when i put the truck in park position and i step on the gas i can barely hear it but wen i put the truck in D , man the non turbo diesel engine come alive , it does in between the range of 0 to 3500 rpm after 3500 it goes away , anyways i can notice a loose of power and torque because i drive a 01 e350 SD and has the same engine but is much much more stroger in the lower end

thanks a bunch

 

Can you tell which side of the engine the sound is coming from? I would also pull the plugs and see if any of them have any signs of a problem.

 

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