If any of you are familiar with semi trucks today, you will notice that most now have a high idle switch in them. It is for the sames principle. At a slow idle not all the diesel fuel is used up in the cycle. This is where the carbon build up occurs, when the fuel is left unburned. Is this a huge problem? I doubt it. IS it something to consider? Maybe. Make it easy on yourself and don't idle clear back. Open it up just a touch. You can actually tell by the sound of the engine when you get there. /forums/images/graemlins/smile.gif
