MY first pic on the forum I got nice black alloys and tires that stick out but you cant see em here. looks sick..anyways

There is vacuum here pretty good at this yellow line in 4x4 hi
This line is on the passenger side of the valve cover.

I FOUND THIS DISCONNECTED its under the coolant resivoir on the passenger side.
No suction while engine is running. again i only tried 4x4 hi

and the red manifold line going to the transfer case is good. Where do I check next i think its the valve on the transfer case but i wanna be sure. i dont hear any vacuum leaks.

Where does the blue line go?

 

My 87 has the same thing, I think its supposed to be like that. I could not find anything it plugs into.

 

its a vent line, thought the same thing. stopped the dealer and say something a tech walked out looked at it and walked back in about about 2 min later he came out said it was a vent line. then i seen it on there as well.