I have a 1995 e320 wagon. I just went through the the vacuum system and checked out the emissions valves. All seem to be ok, but every once in a while I get an EGR code. When it happens it is just after I have started the car. Can be cold or when it is all warmed up. The EGR valve functions ok. I have wondered if the vacuum change over valve could be a problem, but not sure. Any thoughts would be great.