The metal line is from the old pcv system, it was disconnected and rerouted as part of a recall years ago. An easy way to check for vacuum leaks is to spray carb cleaner around the lines, etc and see if the idle is affected at all. Be careful to stay away from the hot parts so you don't start a fire.
Also be sure to check the air box for leaves and other debris, this is a well documented issue that has resulted in many fires. There are a few recent threads that show how to do this.
[This message has been edited by seajai (edited 10-13-2013).]