random

So I was working on the bike tonight and I was getting the fuel lines ready to reattach to the pump because I had the tank off. I looked down and next to the frame there was a random vacuum line that was disconnected. I didn't disconnect this line with the tank and I have no idea what it plugs...

I have a 2005 fz6 with 18,000 miles. Lately it has developed the oddest problem! Only after it warms up, it will randomly die. not stall like it isn't getting fuel, but it's EXACTLY like the kill switch is flipped. If it does this while moving, the bike will/might restart. But it's gotten worse...