Breather hose advice? + poor return to idle.

[RosscoMK3]

I recently bought a replacement breather hose to replace the broken existing part.
The part slots in to the engine fine but I'm stufed if I can remember how it connected to the black box up top. It doesn't seem to reach.
I ripped the old one off over a year ago and replaced it with some hose I had laying around. Now I have no idea if there was another part involved.
Can anyone help?

The car is a golf 1997 with the 1984cc AGG variant engine.

Another annoying thing with this car is that it has a tendency to drop it's revs below idle after the engine has been under load and the clutch is disengaged. If you just rev while in neutral it returns to idle. Sometimes it drops so low it will stall.
Where should I be looking to find the cause of this?

[skatmatt]

Get a scan, I had a similar problem with my VR6 got a scan and found out it was my MAF sensor.

[RosscoMK3]

Get a scan, I had a similar problem with my VR6 got a scan and found out it was my MAF sensor.

Thanks.
I just got my hands on a scan tool so now it is just a matter of getting it working on the laptop.
Out of interest, what is the MAF sensor?

[Ben J]

I think MAF stands for something like mass airflow sensor, its the one connected to the airbox that measures how much air is flowing though. They're fairly common to go bad (atleast on the vr6 i think, probably the same for the 2.0)