1998 Pontiac Firebird Owner's Manual - Page 260

To remove the cap, turn slowly to the left it (counterclockwise). The cap has a spring in if you let it; go of the cap too soon, it will spring back to the right. When you put the back on, turn to the right cap it (clockwise) until you heara clicking sound. Make sure you fully install the cap. The diagnostic system can determine if the fuel has been leftoff or cap improperly installed. This would allow fuel to evaporate into the atmosphere. "Malfunction See Indicator Lamp" in the Index. If you get gasoline onyourself and then something ignitesit, you could be badly burned. Gasoline can spray out on if you open the you fuel fillercap too quickly. This spray can happen if your tankis nearly full, and more likely in is hot weather. Open the fuel filler cap slowly and wait for any "hiss" noise to stop. Then unscrew NOTICE: If you need a new cap, be sure to get the right type. Your dealer can get one for If you get you. the wrong type, itmay not fit properly. This may cause your malfunction indicator lamp light to the capall the way. L Be careful not to spill gasoline. Clean gasoline from painted surfacesas soon as possible. See "Cleaning the Outside of Your Vehicle" the Index. in and yourfuel tank and emissions system may be damaged. See "Malfunction Indicator Lamp" in the Index. 6-7