* Fuel Pressure Regulator (FPR): This is a very common cause. The FPR regulates fuel pressure in the system and often vents excess fuel vapor back into the intake manifold. A faulty FPR can leak fuel vapor into the engine bay, causing a strong gasoline odor. This leak wouldn't necessarily be a visible wet leak but a vapor leak.
* Fuel Injectors: While less likely to cause a *constant* strong smell than a failing FPR, leaking fuel injectors can spray small amounts of fuel which evaporates quickly, creating a gas smell. This is more likely to be intermittent or related to engine operation.
* Evaporative Emission (EVAP) System: This system captures fuel vapors to prevent them from escaping into the atmosphere. Leaks in the EVAP system (lines, canister, purge valve) can allow fuel vapors to escape and create a gas smell. This is a strong possibility given the lack of visible leaks. A pressure test of the EVAP system is needed to diagnose this.
* Fuel Tank/Lines: While you say there are no *visible* leaks, a very small crack or pinhole in a fuel line or the tank itself could be releasing fuel vapor. These are harder to spot than larger leaks. Consider looking closely in low-light conditions or with a flashlight.
* Fuel Filler Neck/Gas Cap: A poorly sealing gas cap is part of the EVAP system. A loose or faulty cap would allow vapor to escape. Try tightening the cap securely and see if the smell lessens (though unlikely to completely eliminate the smell if the problem is elsewhere).
Troubleshooting Steps:
1. Check the gas cap: Ensure it's tightly sealed.
2. Sniff around the fuel system: Carefully check the fuel rail, fuel injectors, fuel lines, and the area around the fuel pressure regulator for any subtle signs of fuel vapor escaping (look for discoloration or residue).
3. Inspect the EVAP system: This is difficult for a home mechanic, but a mechanic can perform a pressure test to identify leaks in the system.
4. Professional Inspection: Given the persistent smell and lack of visible leaks, taking the car to a mechanic for a proper diagnosis is highly recommended. They have the tools and expertise to pinpoint the source of the leak.
Ignoring a gasoline smell is dangerous due to the risk of fire. Addressing this promptly is crucial.
