Iíve recently changed the coil pack and spark plugs all tightened correctly and have noticed when I bring the car to a standstill with the heaters on I can start to smell petrol after being stationary for a couple moments, Iíve checked everywhere and I canít see any leaks, Iíve checked the fuel cap and there is a fairly strong smell coming from there so Iíve ordered a new seal and cap to try that,

Does anyone know if this would probably be a fuel filler cap issue or would it be something more serious with the fuel lines?

Thank you! - Sam