My '97 E300 OM606 has been knocking alot these past few weeks. When cold it sounds bad, like a bag or marbles. Even after it will come up to operating temperature it will knock when the idle is bright up slightly.

In addition I have started using Primrose last tank full. I choose the Primrose for it's lubricating and emulsification properties, to ensure my tank is free from water.

Last week I had replaced my fuel filter and it didn't have visible black particles, assuming I have no algae problem.

When accelerating at sporatic moments I may have a slight hesitation. Sometimes gradually accelerating from a traffic light, I will see some visible smoke behind me, something I never noticed before. Even right after my EGR mod.

And finally I have noticed my mileage drop. Last tank recorded yielded 19MPG and I ride on 18" monoblocks with moderate, non-aggressive driving techniques.

Tomorrow I will top off with fresh diesel and a few ounces of Primrose. I fill up at the same station almost every time, local Hess.

If this does sound like possible injector related issues, what would be a reasonable repair? Replacement of injectors? How striaght forward is replacement of the injectors. I heard that the injectors even if new, must be flow tested. Should I buy the injectors from the local MB stealership and have them test the flow pattern on the spot? My E has about 142,700 miles and thrid owner with no records of such mechanical work. So from my limited knowldge of diesels I am hoping that it is only an injector(s) issue.

Thanx in Advance,
Chris

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'97 E300
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