I need vacuum diagrams for my van?
I looked for vacuum diagrams but was unable to find any in the online repair manuals I have access to. However I was able to narrow down the couple of components that have a vacuum hose. The PCV and the EGR seem to be the only two. I will provide you with an image below that shows the location of the each on the engine. However the IAC utilizes vacuum to help control the idle. It can have an internal vacuum leak but usually only effects the idle.
If you are certain you have a vacuum leak the PCV hose would be an easy thing to check first. Then the EGR.