What Does This Hose Do?

[Jezimp]

Hey guys. Im new to this sote so i appolagise if my termanoligy isnt up to scratch.I brought a 93' r33 not long ago. It has an after market bov, and I'm goin thru the process of fixing the problem of the car stalling and idleing s@*t house. I cleaned the idle control valve and noticed there is a tiny little fitting ( I'm presuming where a hose is meant to be clamped onto) right above the control valve but I'd had a crappy little rubber cap zip tied onto it which was was r**ted so I took it off. Havnt stared the car yet incase it is something major. Just wondering of you can tell me what it does, and if I can just cap it again for now until I out the original blow off recirculator back on??

Any help would be greatly appreciated

Thanks

[Dose Pipe Sutututu]

that would go to the stock boost gauge inside your car

[Jezimp]

Thanks heaps mate, it's has a different boost gauge on the steering colum, not sure where that is getting it's reading from if it's nt hooked to that fitting. If the original boost gauge fitting is not capped properly and is leaking can it cause running issues?