I have a 1996 E300 with 220kmi on it. I highly doubt the chain has been replaced, I also have some white/blue smoke when cold and a little too much clatter. My injectors were tested /shimmed, they are perfect. Tank cleaned, good fuel, no bubbles in lines. Runs very good when warmed up with a little too much clatter remaining. Power is a little weak at bottom end RPM, good as it builds more RPM.

Possible to try adjusting the pump slightly to improve? Please explain steps in doing so, Pics. if possible.
Thanks
Lowflyingbird