How do I know if I have a vacuum leak on a 2000 honda passport?

This can be tricky to solve... here are a couple tips that have helped me in the past... cut about a 3 foot piece of 1/2 inch tubing and use it as a stethoscope to listen for a telltale hiss at and around the intake hoses, manifold, throttle body, and all associated hoses and components... (be careful of belts and other moving parts!) another way is to use a propane torch.. just turn it on (without lighting it) and move it slowly around all suspect areas and if the idle rises noticeably you have found your leak... of course be very careful with this method... do this in a well ventilated area and don't smoke while doing it!... Hope this helps...;-)