Smell of petrol inside the car

I had a similar problem with a 92 when I replaced the float/level sensor in the tank. Did you recently change the pump or sensor?
Check the tightness of anything you may have loosened or opened. There is also a line that usually drains water from the depression in which the filler cap sits. If you have a bad cap and even a minor overflow or spill from a fill-up, gas could leak into the trunk and once absorbed into the carpeting it is very difficult to remove the smell from the matting. I power washed mine with solvents and water based detergents, three times and let them air dry each time, finally placing an odor absorbing chemical in the trunk to solve the problem. Good luck hope this helps.