firebird gas fumes

I have a '96 Firebird Formula and I'm having a problem with the smell of gas inside the car only after the car has been driven. I've checked under the hood and there is no smell anywhere there, only inside the passenger compartment. After the car sits for about 1/2 hour or so, the smell is gone. Start the car again & drive it, the smell comes back. Like I said I've checked under the hood & theres no smells or leaks there. Other than the smell the car drives & runs great!!........any ideas?

Hows your gas mileage?

I have a '96 Firebird Formula and I'm having a problem with the smell of gas inside the car only after the car has been driven. I've checked under the hood and there is no smell anywhere there, only inside the passenger compartment. After the car sits for about 1/2 hour or so, the smell is gone. Start the car again & drive it, the smell comes back. Like I said I've checked under the hood & theres no smells or leaks there. Other than the smell the car drives & runs great!!........any ideas?
gas mileage is very good!!!!!!, can't find any leaks anywhere

May be a evap canistor issue or solenoid.