My 95' firebird is losing gas?

[cody]

Im not sure whats wrong can anyone help?

When i go out driving with a full tank. and whenever i stop i can smell gas fumes inside the car, alot of fumes.. I have no clue what the problem is but it seems to be killing my gas mileage, can anyone help?

its a manual.
3.4 v6
all stock

 

[melsg5]

Since gas fumes are potentially explosive you should take the car to a shop immediately. Guessing what the source is wont resolve your problem.