Model and Year Model: 1997 Monte Carlo

Went to start my car yesterday, but it didn't quite fire up. Looked at my woman and said "Do you smell something burning?" Whatever...go to start it again, and it keeps reving as if I'm holding down the gas pedal (which I wasn't). I shut it down, popped the hood, and on top of the engine it looks like there is a piece missing, a little hose or something, that looks like it definitely should be there. Any info would be greatly appreciated, as I'm not real car savvy!

I've had suggestions of a vacuum or PCV hose so far.