Gas smell inside car

You may be smelling a fuel leak, exhaust leak, or the heater core could be leaking. It's hard to know without actually smelling the odor and inspecting the vehicle, I suggest you take it to a shop, have the technician smell the odor and see what they suggest.

I noticed under Recalls that the O-rings on the gas lines (rails) to the fuel injection can leak under the hood on higher mileage cars. Could be the gas smell comes into the car when using the heater fan?

Take to mech.have evap system chcked. Ours had gas in one canster and solnoid.Caused by overfilling.