96 accord. When vehicle is sitting , idleing with the heat on,bring air in from outside i get a gas smell from the vents.When vehicle is movingthere is no problem with gas smell.

 

How about maybe a leak in the floorboards and the fumes are floating up?

 

Sounds like you have a small gas or exhaust leak. Does it smell like fresh gas or burnt gas?

Probable places for a fuel leak:

-Fuel injector seals
-Banjo bolt for the fuel line on the fuel rail
-Pressure fitting on the fuel rail
-Fittings at the fuel filter

Probable places for an exhaust leak:

-Exhaust manifold gasket
-Downpipe gasket
-Catalytic converter gasket (either end)

Forgot something...

Pop the hood of the car and turn the key to ON/II to pressurize the fuel system. Go back under the hood and smell for gas. That would be an easy way to tell if its exhaust or fuel.

 

Check for leaking fuel line running under the left side floorpan.