Pontiac 2004 Grand Prix Owner's Manual page 288

5-8
The fuel cap is located
behind a hinged door on
the driver's side of the
vehicle.
While refueling, let the fuel
cap hang by the tether
below the fuel fill opening.
To remove the fuel cap, turn it slowly to the left
(counterclockwise). The fuel cap has a spring in it; if you
let go of the cap too soon, it will spring back to the right.
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CAUTION:
If you spill fuel and then something ignites it,
you could be badly burned. Fuel can spray out
on you if you open the fuel cap too quickly. 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.