Gas smell

Hello I am new to this site so bare with me.
I have a 97 runner I have had it 16 years has 200867 miles I have babied it from the first day I bought it stay up on all of my maintenance just recently I have been having a strong gas smell coming from my tail pipe I just had the timing belt water pump done 8000 miles ago air filter 02 sensor spark plugs wirers and catalytic converter less then 2 years ago I work fora Lexus dealer and they are telling me it is the catalytic converter so I have my mechanic take it back to the place he got it from and they are saying nothings wrong with it i have no check engine light on and no one can pull any codes everything that has been checked shows good any suggestions

 

if your mechanic checked it out and they can't find anything wrong i wouldnt worry too much. is the smell entering the passenger compartment?

 

place some cardboard under your gas tank forward, check for leaks while its off, then start and see if it leaks, lines wear out over time, could be hole in tank or the gasket for the sending unit could be no good, even the filler neck could leak if no good, if no leaks then have the guys at your job check it if they think or it might not be anything or its above my knowledge

 

Also could be your charcoal canister, any of the emission items that can go wrong can cause a rich fuel mixture.......