So I bought a 1998 E350 club wagon with the 6.8L v10 engine. It is running rough under load so I started with replacing the sparkplugs. When I was in there I noticed that the intake and cylinder head don't line up on the rear of the engine on the passenger side. There is an open port on the head that has a gasket but it doesn't line up with the intake. The pipe above the port is a coolant line. I bought this van from the Search and Rescue team I volunteer with and we have had this van for some time and it has always seemed to work fine. What is this port for and what flows through it?