Kewl that you are able to eliminate the EGR as a problem. Had a friend that had an idling problem and this was it.
Didn't mean to harp (if that's what it sounded like), and didn't have all the info from your last post, so I decided to explain in detail, not knowing your level of expertise, and to help anyone else in later searches.
From what you're saying it acts like (rich at all rpm's), sounds like it could be the CHT sensor....