[Tomnavigator]

All,
Thanks for your comments. I started this thread hoping to generate a good discussion on carbon buildup. I would like to add information and present another view on a few of the comments I saw on this thread.

1) I live four miles from the Citgo oil refinery near Lake Charles, LA. There is a bulk fuel terminal that loads gasoline and diesel into 18 wheelers. The loading terminal loads Mobil/Exxon trucks, Valaero trucks, Chevron trucks, Texaco trucks, etc. Everyone gets the same fuel. The only difference is the additive. There are at least six tanks labeled Exxon/Mobil additive, Texaco additive, Chevron additive, etc. Every trucks get the same fuel and a certain amount of the appropriate additive. All the oil companies work together this way around the country. All gas stations near a Chevron terminal gets Chevron gasoline. Only the additives change. Think about it. It makes sense for the companies to work together this way so they all don't have to have terminals in every geographic location. The fuel is the same no matter which station you get it at. Only the detergent additive is different.
2) I think most people buy diesels in an effort to save in transportation costs. I drive 140 miles (round trip) to work each day. I bought a diesel to reduce my costs. The only low cost (practical) ways to prevent CBU is to install a catch can and/or eliminate the EGR. I don't want to bypass my pollution prevention devices. However, I would prefer that my car runs. So far I have not blocked my EGR because this will effect the NOx and therefore the SCR system that injects the urea mixture. I am waivering on blocking the EGR because I don't see any cost effective alternative.
3) I still wait for someone to learn to code out the EGR and charge a reasonable fee for this service. I don't want a performance tune that creates new problems. I don't want to spend thousands of dollars to have a dependable car. Any modification I make must be cost effective and increase reliability.