A car can smell like gas for several common reasons, typically due to fuel vapors escaping or fuel not burning properly. Here are the main causes:

• Loose or damaged gas cap: If the gas cap isn't properly sealed, fuel vapors escape from the tank, causing the smell.
• Fuel leak: Leaks from fuel lines, injectors, or the fuel tank can cause gasoline odors in and around the car, and these are serious safety risks.
• Faulty fuel injector: If leaking or malfunctioning, it can release gasoline vapors.
• Fuel system issues like a failing evaporative emissions system (EVAP) or charcoal canister may let fuel vapors escape.
• Unburned fuel entering the exhaust due to worn spark plugs, bad oxygen sensors, or a rich fuel mixture can cause gasoline smell from the exhaust.

It is important to address the smell promptly, especially if due to leaks, since gasoline vapors are flammable and hazardous. Checking the gas cap for tightness and damage is a good first step. For fuel leaks, injector problems, or EVAP faults, a professional mechanic should inspect and repair the vehicle. Avoid driving if a fuel leak is suspected to prevent fire risk.