this is the noise that persists after replacing the nozzles and pop testing them to within 40 psi of each other. As the video description says, during a diesel purge all the knocking noise goes away.

any suggestions?

https://www.youtube.com/watch?v=HJsxVluVOhU&feature=youtu.be

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'92 300D 2.5
'99 E300TD