Don't think you have a vacuum line on the air box. I'd bet if you follow it to it's origin, you'll find it is the crankcase vent tube attached to your valve cover. Put your hand near the end of the tube you removed with the engine running.....is it puffing air?....if yes...it's what I said it was. Do not plug it...zip tie it somewhere out of the way, or make a catch can, and attach it to that.
