Originally Posted by Redrider94
Rollover valve if you look on top of the tank you will find a hole that it goes in
^ this, there are two on top of the tank, the hoses tee into one that goes to the evap canister under the hood. They allow vapor to vent to the canister to prevent pressure from building in the tank and have a valve in them to prevent fuel from spilling in a rollover. Normally if they fall out, it's because the rubber grommet that holds them in the tank has rotted away. You can get new grommets from a dealership, I think there fairly cheap.