Revving - WHERE do those vacuum lines go?

[jennina1]

95 Disco after warming revs, & stalls at idle.
I have replaced the IAC, VSS, cleaned MAF,
replaced both O2 sensors, water temperature sensor,
no help. After the first O2 sensor was replaced (44 code was evident)
I cleared the code and it came back...

I think it is a vacuum problem.
There is a vacuum line that is between the plenum and firewall, near
the stepper motor / IAC - it is currently plugged and does
not go anywere.

As well, the vacuum switch that opens and closes the water flow to and from the heater core is not hooked up to anything.

I have been all over the forums, RAVE cd, and everywhere else I can think to find out where these vacuum lines go to...

Can someone that has a 3.9 please help me?

[ihscouts]

Near stepper motor, probably cruise control. I don't know about the heat control, maybe someone else does.