I have a 1988 560SL. I just went and had it smogged tested. The technician had me replace the EGR valve. After replacing this lovely and economical item the technician pulled a vacuum on the valve and the engine idle was not effected as it should have been (according to him and the the mercedes shop manual). He said that the system has a carbon clog and needs to be cleaned.

Could someone give me some advise on how to remove the carbon clog. The clogged end of the tube appears to be at the connection on the very inaccessable rear of the engine.

I have tried a wire down the tube with little success. Is there a carbon remover I could try?

Patrick