The grommet fits in a hole in the rear of the lower intake. It's hard to get to on most cars because of the wiring harness and the egr/fuel pressure regulator that are kind of in the way. As others suggest, I'd replace the grommet, pcv, hose, and the metal screen/oil trap. Cost less than $20 for all of it. Get the screen, grommet and valve from the dealer if you want to assure a nice tight fit and no vacuum leak.