If the EGR is truely inoperative then plugging the line with a BB will just give you peace of mind. The only possiblility, and its a small possibility, is the EGR is stuck partially open and constantly backfeeding exhaust into the intake. The easy way to fix this is to remove the EGR and make a thin plate out of aluminium using the EGR gasket as a template. This plate has no hole in it to allow gasses through and simply installs underneath the EGR valve to totally and completely block off the opening. Sneaky, cheap and effective.

You likely have an ARV valve on your turbo as well. This can be disabled easily as well and your highway throttle response will improve. Do a search on ARV. RT

__________________
When all else fails, vote from the rooftops!
84' Mercedes Benz 300D Anthracite/black, 171K
03' Volkswagen Jetta TDI blue/black, 93K
93' Chevrolet C2500HD ExCab 6.5TD, Two-tone blue, 252K