Engine and gas smell through air vents

When I'm driving my 2004 hyundai tiburon gt tuscani edition v6 2.7L 6 speed manual at low rpms it sounds like something is grinding in the engine, should i be concerned about this? can someone help me diagnose the problem

Also When im at neutral and my foot is on the brakes and i have the cold air on, i can smell gasoline through the vent and it happends only at that time