Hi there, I am sorta new to the forum, first post.
My truck has 95k miles. For about a year I have been hearing this faint knocking sound from the engine under medium acceleration. It happens only at between 1500 to 2000 rpm AND only in 4th 5th and 6th gears. It doesn't do it at idle. Also can't hear it under hard accelerations. Any ideas? I can work on gas engines but never fixed anything diesel before. Been reading about these injector and fuel pump noises but have no idea what they sound like. This noise definitely sounds like from the engine.

Thanks

 

When my injectors went bad (yes Ive had to replace all 6 like alot of us) my stick shift would vibrate at lower rpm's and could hear the turbo pulsing. Its probably injectors. Be prepared to replace all 6 and get a 2 micron fuel system.

 

Thanks for the reply.
I don't have any of those symptoms you had. If I pull my injectors out for inspection, will I see if they are bad? Can they be rebuild?