The whole fresh-air duct have been removed from my 2004 high power by previous owner, so intake goes through airbox only. Just realized that I'm missing at least one vacuum hose which is sucking air from engine bay because of that. Engine is working fine without that hose but I guess it would be better to plug it somehow(?) At least on idle it didn't seem to have any effect did I plug it by my finger or not. Even thou it must have some function. Attached is the image of the place that I'm talking about.

So how is it done on those aftermarket intakes. Do they use this "intake switch" or is it plugged? Because of that removed fresh-air duct am I having some other problems that I should be aware of?

 

Yes, problem.

That end of the hose, no concern, but the hose joins the manifold just under and behind the throttle plate, pointing down - make certain it's properly capped off.

 

So there's also another hose joint. Thanks for the tip. Have to find that and cap both. Just wondering would it give wrong info for the computer if those hoses are capped or open (like in my case) and it would run engine too rich for example?

 

By the other hose I guess you ment this one (attached)? That seems to be in place and it goes all the way to manifold.

On this image:

Looks like the hose (M) that I'm missing goes to some sort of tray that's holding the air cleaner and from there to this fresh-air duct. Well I'm missing this "tray" as well.

This image show's all the hoses:

Seems that this whole fresh-air duct is only available on high power version. If it only controls the valve I guess it should be safe to cap it.

Just were reading this K&N installation sheet. If I'm not reading it wrong they connect this hose for something. Do they have fresh-air duct in place which have no purpose?

 

you can remove that whole frest air duct assembly if you wish without ill effects...just make sure that you put a rubber cap thats the proper size to seal where the end of that hose connects to the manifold just behind the throttle body as you see

 

Found the VFAD remove thread, it explains it all. Thanks for help!