That's not the air valve. There's a discrepancy regarding the aftermarket part manufacturers terminology vs Toyota's. We call that part the AC Idle-up Diaphragm. To find out more about it
CLICK HERE and scroll down to the middle of the page.
You don't need to remove the cylinder head to remove the air valve. You just need to remove the top half of the intake manifold. Of course that's not quite as easy as it might sound. There's a lot of other little things that need to be removed before you can do that. You might want to read the
Hose of Death thread and cut an access hole in the back of the engine hump (as shown there). Having that access hole is an enormous help when removing the metal pipes from the back of the upper intake. Search the site for for more information on the other steps. Threads that discuss head gasket jobs should mention steps for removal of the upper intake. The information is here, the trick is finding it. If you're not having luck with the site search feature, use Google or other similar search engine (as talked about
HERE). Tim