Iacv is located on the back of the intake manifold - it has 2 coolant lines connected to it, and an electrical connector. Remove it from the manifold and clean it w/ carb cleaner. That should help the idle

If youre not sure what the tapping is (and it could be valves) you should not attempt to fix this yourself - you can really screw it up worse, if you dont know what youre doing.