I’m not familiar with Toyota’s fuel systems, but it’s probably like most cars of this era where the fuel pump is located in the gas tank and has a rubber o-ring to seal it. It wouldn’t leak except when the tank was full, because it’s located on the top of the tank. If the fuel pump has ever been replaced or was replaced just prior the the gas smell it could be the o-ring is not sealing the top the tank correctly. Many cars have the fuel pump accessible from under the rear seat. If your’s does I’d remove the back seat and see if that’s where the problem is. I’ve seen this to be the problem on other cars.