If your vehicle is showing strong smell of raw, unburned gas, here are the most likely causes and the parts you'll need to fix each one.
A loose, missing, or degraded gas cap allows fuel vapors to escape directly into the air. This is the most frequent cause of a gas smell and often triggers a Check Engine Light.
Rubber seals on the fuel injectors dry out and crack over time, causing pressurized fuel to leak onto the hot engine. This is also a very common installation error where the O-rings get pinched during intake or injector work.
The evaporative emissions system is designed to capture and burn fuel vapors. A cracked canister, stuck purge valve, or faulty vent valve will vent raw fumes into the atmosphere.
Worn spark components prevent the air-fuel mixture from igniting in the cylinder. This pumps raw, unburned gas directly out of the exhaust pipe.
If the fuel pump was recently replaced, an improperly seated gasket or loose lock ring will allow raw fuel and vapors to escape from the top of the gas tank, especially after a fill-up.
A rusted fuel filter housing or improperly tightened fittings from a recent filter replacement will cause pressurized fuel to drip under the vehicle.
A mechanically failed fuel injector can stick open, constantly spraying fuel into the cylinder. This floods the engine, causes severe drivability issues, and creates a massive fuel smell.