Ok, so I just got a new Cold Air Intake (cheap eBay one) and I've noticed there a hole for a sensor and two nipples coming off the side. One of them goes to the valve cover but what does the other one hook up to? Is it needed or should I just cap it off? Thanks in advance!
There's a vacuum line that connects to the elbow coming out of the stock air box. That's probably the other connection. Right-angle boot connector just below the center of this picture: