Smell of gas coming from exhaust?

i own a repair shop ,and you need to take it and have it put up in the air,and look around the tank area for it,theres a small possibility it may have a tiny pin hole in the gas tan on it causing this to happen,and that might be what your smelling,either that or a loose hose on it ,either way it needs to be checked out really good,if its raw un burnt gas its dangerous to drive it like that,good luck i hope this helps.

Carbon Monoxide doesn't smell, the fact that you can smell it while the windows are down suggests more a gasoline leak form the tank, probably on the top of the tank making it difficult to see.

Look very carefully at your gas tank, recent spots from a gas leak will leave trace marks (Streaks) from its' passage.

Is the car back fireing and if not are you sure you don't have a fule leak? The problem from what you say only seems to happen when the car is running.

You may have one spark plug that is not firing.

To find out which one it is, with the engine COLD and Windex spray bottle handy,

1) start the car.

2) Spray the exhaust manifold to see which exhaust port is NOT getting hot. That sparkplug is not firing.

the best answer i could give is that your running really rich. look to see if there is a carbon deposit on your exaust. (rub your finger in the tip and if its really black your running rich) alot of times its just the oxygen sensor but it could be other things as well.

it's one of 2 things what are bad and need to be replaced.

#1 O2 Sensor.

#2. EGR.

check if u have a leak if not i wouldnt worry to much ,it am 89% sure it will pass inspection