Pontiac Wave 2008 Owner's Manual page 226

Hatchback shown. Sedan similar
The tethered fuel cap is located behind a hinged fuel
door on the passenger's side of the vehicle.
To remove the fuel cap, turn it slowly counterclockwise.
The fuel cap has a spring in it; if the cap is released
too soon, it will spring back to the right.
5-8
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 3-48.