What does this line go to?
 

I just noticed this line today after I saw the liquid that seems to have leaked from it. When I shut off the car I could hear and feel a constant hissing of air pressure coming out of it too.

Looks like previous owner cut and crimped it when he did the RB25DET swap and it seems to have opened up. I'm just wondering what it originally went to and if it is okay for me to just re-crimp it and leave it the way it is.

http://i68.tinypic.com/23mrbiq.jpg

Pretty sure that’s the EVAP. Helps get rid of fuel pressure in the tank or some bullshit like that. Really just emissions bullshit. Cut it out or leave it, doesn’t matter

Ah, that might be why my tank seems to have an excessive amount of pressure when I take off the fuel cap.

But then what is that liquid that seems to be leaking from it onto the clutch cylinder?

What does it smell like?

I have a terrible sense of smell, but I started the car and watched it and after about 5 seconds it started spraying a mist of liquid... I used a paper towel I had (that already had WD-40 on it) to soak some up and I'm pretty sure it smelled like fuel, but it doesn't look like fuel. I'll take a better look at it tomorrow.

On my s13 that cut line goes to my clutch master cylinder. Or looks like it but you have a working clutch so that can't be it!
Best bet is to follow the line to the end.