1996 GMC Sonoma Owner's Manual - Page 228

1CAUTION: If you get gasoline on yourself and then something ignites it, you could be badly burned. Gasoline can spray out you if you open the on fuel filler cap too quickly. This spray can happen if your tank is nearly full, and is more likely in hot weather. Open the fuel filler cap slowly and wait for any "hiss"noise to stop.Then unscrew the cap all the way. Be careful not to spill gasoline. Clean gasoline from painted surfaces as soon as possible. See "Cleaning the Outside of Your Vehicle" in the Index. When you put the cap back on, turn it to the right until you hear at least three clicks. Make sure you fully install the cap. 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" in the Index. NOTICE: If you need a new cap, be sure to get the right type. Your dealer can get one for you. If you get the wrong type, it may not fit have proper or venting, and your fuel tank and emissions system might be damaged. 6-6