Well I can only go by my 8v GTi, forgot to ask you if you have a K-Jet or what, but i'll post this anyway, I assume it is different on the carb models.
1. Looking at the side of your airbox, at the very bottom there should be 1 line running to the side top part, there are two inlets, it should go to the lower one.
2 & 3 & 4. Just above that there should be your 2nd vacuum hose. This one runs over the airbox to a Y splitter, from which 1 part goes into the fuel (EGR?) valve (round thing next to the injector rail) and the other side runs to the right port of the throttle body.
5.Looking at the throttle body where no. 4 just went into, just left of that port should be another which should be blocked by a rubber cap.
6.On the back of the throttle body (opposite the other 2) there should be another port which is blocked off.
7.If you look at the right hand side of the intake manifold, there is another vacuum line which comes off the brake booster line. This line then leads to the MPG vacuum gauge on your clocks.
Also you should check all rubber intake hoses for cracks, splits, holes ect. Including the main one from the airbox. Take it off turn it around in your hands and check everything. Other hoses would be the one to the ISV, from ISV to Intake, booster line and PCV valve.
I think that was all

If everything is fine, one could assume something is wrong with the vacuum thing on the clocks itself, how high the chances of that are I don't know!
Cheers