Originally Posted by MaxOctane

Well, don't want to sound too negative, but I am pretty sure a crack in that hose won't create your problem. I think that is the valve cover breather hose. It lets pressure out of the valve cover and should take it into the intake through the throttlebody. Additional pressure will open your PCV valve and go directly into the intake. While you should fix that hose, I fairly certain it won't fix your problem. I still think that your idle problem is a vacuum leak. Check all of your vacuum hoses and make sure none of them are cracked.....