I cleaned my intake when I had it off for paint and aside from lots of buildup in it from the pcv system the flaps or butterfly vlaves as i called them seemed free and operational. You can feel them open up around 3000 or 3500 rpm when driving, so it seems they still are ok. New gaskets were used when reinstalling it. I will get new ones again for the new one and might lay a thin bead of sealant on both sides of it this time also as a precaution.