My car was making the same noise as this link http://www.youtube.com/watch?v=_O8qS...eature=related . So I had my local mazda dealer run the diagnostic test on my car. Sure enough they said the problem was my intake manifold. So I buy the part and replaced it. The replacement went smooth however I ran into one problem. I am unable to remove what seems to be a cap from the new manifold. The cap is covering a vacuum hose that I need to connect. Anyone have any idea how to remove this cap. I have attached pics to this post I circled the location of the cap that I need to remove in red. The cap does spin left and right but it does not go up or down or at lease I could get it to move up or down. Please let me know if you have any ideas.