Why Does My Chevy Truck Smell Like Gas?by David Reber
A gasoline odor emanating from your Chevy pickup might indicate a problem and a fire hazard. If yours is an older Chevy truck, it might be less of a problem and more of an unnecessary nuisance. Either way, find and correct the source of the gas smell as soon as possible. Fuel odor may occur due to leaks or improper engine operation.
Gasoline odor may come from leaking fuel somewhere between the tank and the engine. A leaking gas tank may emit gasoline odor all the time, while leaking fuel line(s) may leak only when the vehicle is running.
If fuel is taken into the engine but fails to burn, it will give a gasoline odor to the exhaust. Faulty ignition components such as spark plugs, ignition wires, or distributor components may cause ignition failure. One or more cylinders on your Chevy truck might not be firing -- meaning that fuel's going in but not burning.
If your Chevy truck's engine valves are not closing properly, fuel may be forced out of the engine prior to ignition. Unburned fuel may exit through the exhaust system or may be forced backward through the intake system (perhaps causing backfire).
Many older Chevy trucks use carburetors, and it's not unusual for gas to pool at the area where the fuel line connects to the carb or to the filter, or to pool within the carburetor itself. In such a case, a gasoline odor would be strongest right after you've turned off the truck's engine. As time elapses, the gasoline pooled in the carburetor, and the corresponding odor, will dissipate. It might take an hour or several days.