Well, I've certainly got a range of opinion on what the problem could be.

The diesel mechanic came by to take a look, but unfortantely I couldn't see with my own eyes how he made his diagosis.

The mechanic says that the problem is a bent intake valve on #3 piston.

I expect I will go with the mechanic, but am open to any board wisdom. Like I said, I couldn't hear the problem with a stethoscope on the valve cover, but heard the problem lower down and when I crack open the injector for # 3, the engine slows and idles rougher.

And if the diesel but non-mercedes mechanic fixes the bent valve problem, is there anything that I should be particularly aware of.