I have a GMC 05 cc lb 4x4 dually, when going thru the gears at higher rpms there is a rattling sound kinda like valves on a gas engine....i do realize this is a diesel engine but this noise is not constant, it comes and goes towing #9000 or empty....had an 04 same as above mentioned it did not ever make this sound in 30,000 miles...and 04 seemed to have more power.

Any

The pilot injection turns off at 2500 or so rpms, greatly increasing the noise of the engine. Seems to do so more on some motors than others. Sounds to me like that is all that is happening.

does the pilot injector shutting down affect the power.