Lubro Moly Diesel Purge - Did Nothing to Solve my Problem

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Here's the facts:

1983 Mercedes 240D. Factory Crate Motor with only 25,000 miles. Idles like crap and gets worse around 1150 RPM with the engine shaking wildly from side to side. Above this RPM, the engine smooths out and runs fine with lots of power.

I ran 2 cans of Lubro Moly Diesel purge through a seperate container, with absolutely no effect whatsoever. Still idles like crap.

I called Ditmire Motor Works which are Mercedes Diesel Specialists not far from where I live and I told them my situation and given the fact that Diesel Purge did not help me at all, I suspect my timing might be off. They said the timing on these engines almost never needs to be adjusted during the life of the engine. He was certain that one or possibly all of my injectors are dirty and need to be cleaned - which I thought the Diesel Purge would have done for me, but it looks like I need to tear into the injectors now. Can I clean these things, or is it better to buy new ones?