[Christ]

Well, not exactly tongue in cheek, but I did know that it wasn't correct.

EGR recirculates exhaust gas back into the combustion chamber to lower combustion temps so that Nitrogen doesn't combine with other compounds to form NOx, as I understand it.

Of course, if there is unburned fuel in the exhaust, part of it will go back through the EGR system. Not 100% about it, but I believe that to be the reason for sludge/yuck buildup in the EGR passages (unburnt or partially combusted fuel mixture).

I posted it like that because I was waiting for a response, as I frankly don't think he has any idea what it does, either. I was just trying to verify by leading. Lawyers do it all the time!