Gas smell in a car can be serious. It’s often caused by fuel-system or evaporation-system issues rather than just a bad odor, and some problems can pose fire or health risks. Here’s a practical, step-by-step guide to understand potential causes and what to do. What the smell might indicate

• Fuel leaks in the engine bay or fuel lines: A leaking line or hose can allow gasoline to pool or spray, creating a strong gas odor and a fire risk. This often requires immediate inspection and can be dangerous, especially if the smell is persistent or you see wet fuel or dripping spots. If you suspect a leak, stop driving and seek roadside assistance or a tow to a shop. [General guidance from automotive safety resources]
• Evaporative Emission Control System (EVAP) problems: The EVAP system captures fuel vapors from the tank and fuel system. A faulty or damaged EVAP component (such as a loose gas cap, cracked charcoal canister, or faulty purge valve) can let fumes into the cabin or surrounding area. A failing EVAP can trigger a check engine light. [EVAP system overview]
• Loose or faulty gas cap: A cap that’s not sealing properly can allow vapors to escape and produce a noticeable odor around the vehicle. Replacing a damaged cap or tightening a loose one often resolves this. [Common and simple cause]
• Exhaust or intake leaks: If there’s a small exhaust leak or a poorly sealed hose near the engine, fumes can enter the cabin, especially when conditions change (cooling/warming, acceleration). This is less common but important to check. [Exhaust system mentions]
• Fuel injector or fuel-pressure issues: A stuck-open injector or rich fuel mixture can cause more fuel vapors or odors. This typically accompanies other symptoms like rough idle, misfires, or performance changes. [Fuel system notes]

What you should do now

• Do not drive if you smell gas strongly or hear hissing sounds, see streaks of fuel, or notice the odor intensifying near the engine bay. Gasoline is highly flammable, and leaks can pose serious fire risks. If in doubt, have the car towed to a shop. [Safety guidance]
• Inspect basic items first:
  • Check the gas cap: ensure it is snugly tightened until it clicks. If the cap is cracked, damaged, or missing, replace it.
  • Look for obvious signs of leaks under the vehicle or in the engine bay after parked for a while; a fuel leak can appear as wet spots or staining.
• Get a diagnostic scan if the check engine light is on: A code reader can identify EVAP or other fuel-system faults and guide the repairs. If the light is on, avoid driving long distances until diagnosed. [Diagnostic relevance]
• Have a qualified technician inspect: Fuel system leaks, EVAP components (including the charcoal canister), fuel pressure regulator, injectors, hoses, and clamps; and check for exhaust or intake leaks. They can perform fuel-pressure tests, smoke tests for EVAP leaks, and inspection of connections. [Repair guidance]

When to seek urgent help

• If you see fuel dripping, hear a hissing sound, or the odor is very strong, treat it as an emergency risk. Stop and call for roadside assistance or emergency services if necessary. [Safety protocol]

If you’d like, share your car’s make, model, year, and any symptoms (check engine light on, recent work done, location of odor, when it occurs), and a more tailored set of probable causes and next steps can be given.