You could try the egr shunt as devised by Kartek (forum member )
This will cost a couple of $ and stop the egr valve working. Now if its sticking open you will still have trouble and its probably best to remove it and clean it anyway.

Biodiesel will not cause any issues.

I have the same question. I have heard that we will be seeing a higher percentage of fuel retailers that will be dispensing a 5% minimum Bio content in their Diesel fuel. There is a station that is advertising B20, but the "fine print" on the pump says "UP TO 5% Biodiesel content". I will be filling up my car with pump Diesel this week, so I will find out soon enough if the Bio was the problem or not.

I have heard about the EGR shunt, and am willing to try it as long as it is reversible. Every 2 years our Diesels get smogged here in CA, so this mod may cause it not to pass if it was still in place.

Usually bio diesel will smoke white when the engine is cold (below 40 degrees). Haven't heard much of it blowing black smoke with a warm engine.

The car rolls coal upon acceleration, regardless of what fuel is in the tank, bio or otherwise. I just added six gallons of pump Diesel to the tank, so tomorrow morning I will see if it starts without any input from my right foot. I know that is not a definitive solution, but it may get better as the bio gets diluted every three or for days when I top it off with D2.

Here is the official Mercedes-Benz Biodiesel Brochure

Illinois MB Biodiesel Brochure "Yes, you can own and drive a MB diesel in a B20 mandated state"

I'm not sure biodiesel is the issue, as much as a lack of maintenance by owners. Oil change (and fuel filter replacement) intervals should be halved when using higher blends (B6-B20) and a multi-functional additive needs to be used regardless. Other than the additional lubricity and renewable energy factor, biodiesel doesn't offer much benefit to the engine or fuel system, especially on the newer CDI and BlueTEC diesels with their higher fuel pressures, hotter temperatures and complex electronic injectors with smaller passages.

A number of OM642's have reportedly seized due to sludge, whether from the biodiesel fuel dilution issue described in the brochure or just lack of maintenance. Several updates to the ECM were apparently released as well. I would inspect for sludge and make sure the latest updates were installed if I owned a V6 BlueTEC car/SUV for sure.

With that said, I wouldn't hesitate to use B10-B20 where mandated. You can have a lot of the same issues (fuel system and injector deposits or gelling) running straight diesel without additives.

I happened upon this: CDI3 EGR bypass mod | Mercedes-Benz Owners' Forums

I am fairly certain my EGR is bad, and this should fix it. I have also seen EGR emulators available on ebay. Not sure if I trust these, but would probably build and install my own. Thoughts?

If you can bypass the ERG in any way, you'll be ahead of the game regardless if it solves this specific problem or not. But, I think there's a good chance it will!

Diesels simply were not intended to function with EGR. It also, does extremely little in terms of emissions control on a diesel, it's only mandated because the EPA can't apply logic to regulations...if a gas engine has to have it, then by their logic so must a diesel engine. I actually think EGR harms emissions control on diesels.