hello,i have a b16a2 engine. when you look at the engine from the front of the car, the intake manifold on the back right hand side has a nipple that sticks out. What part is supposed to connect to this? i believe it is a vaccum source? previously i believe it was hooked up to my blowoff valve or my boost controller, i cant remeber. Any ideas on whats supposed to connect to it? car idles crappy when the nipple is uncovered.