Why not EGR? Sounds reasonable. Is the IAC valve sticking when cold? Is the MAF voltage reading correctly? (I ask this because I have seen one case where a K&N filter that was overlubed got a touch of oil on the MAF wire and was not able to be cleaned causing a bad reading.) I would suggest a second opinion. You may find it easier on the shop if it is left for a few days, to allow for a cold condition to replicate it.