It is part of the hydraulic tensioner and without it, the chain is riding on a metal surface.
I am sending you the entire removal procedure for the timing chains. I also have the diagrams for the front cover and the chain guides themselves.
You will have to remove the front cover, locate the piece and loosen the timing belt and install a new guide.
You should do theis AS SOON AS POSSIBLE.
Images (Click to enlarge)
Monday, October 17th, 2011 AT 9:05 PM