My wifes kid brother just bought what he says is an f-250 high boy with a 400. I know next to nothing about this kind of stuff so here goes. The truck will not idle. He has checked the vacuum lines and all are ok. There is a missing line with suction coming out of the back of the intake manifold near the firewall. Cannot find what it may go to. Blocked it off and it seemed to at least try to idle. Distributer has no moisture in it and looks pretty good. The spark plug bases are rusted so I told him he probably needs to yank em and look at em. Made sure he did not mix up firing sequence. Quite a bit of oil blowing out of vacuum barb on back of manifold. Carb is a 2 barrel motorcraft. Any help would be appreciated. Thanks.