I'm having a little problem with the vacuum lines on my H22 civic. I got everything pretty much the way it should be except for a vacuum hose on the intake manifold. According to the vacuum diagram, on the back of the Intake manifold there is a vacuum line that goes to the black box beneath the manifold. Just one. On my Intake manifold there is another tube right above the one that goes to the black box. Where does this one go to? If I just cap it, the RPMs go way down, to about 400. Any help would be appreciated. Thanks.

 

your talking about the IAB box, I don't have a diagram but if you search h22 IAB you should find some info

 

The one above your IAB connection is not used. Cap it off. The only vacuum connection that you absolutely MUST have is for your map sensor. You can actually cap all the other ones off.