Pontiac 2008 Vibe Owner's Manual page 222

To remove the fuel cap, turn it slowly counterclockwise.
On some vehicles you may have to push in while
turning the cap.
While refueling, hang the fuel cap inside of the
fuel door.
5-8
The fuel door release lever
is located near the floor
under the driver's seat
on the outboard side.
CAUTION:
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Fuel can spray out on you if you open the
fuel cap too quickly. If you spill fuel and then
something ignites it, you could be badly burned.
This spray can happen if your tank is nearly
full, and is more likely in hot weather. Open
the fuel cap slowly and wait for any hiss noise
to stop. Then unscrew the cap all the way.
Be careful not to spill fuel. Do not top off or overfill the
tank, and wait a few seconds after you have finished
pumping before removing the nozzle. Clean fuel from
painted surfaces as soon as possible. See Washing Your
Vehicle on page 5-85.
When replacing the fuel cap, turn it clockwise until
it clicks. Make sure the cap is fully installed. The
diagnostic system can determine if the fuel cap has
been left off or improperly installed. This would allow
fuel to evaporate into the atmosphere. See Malfunction
Indicator Lamp on page 3-36.