Lexus Troubleshooting Questions? Ask a Lexus Expert
I have replaced many fuel caps for this issue.
As an experiment, can you smear some vaseline on the filler cap rubber seal, then screw it back on, and then see if the smell is still there, or is less, or completely gone?
I you only smell it in the interior and not the garage, this is a good place to start.
Have you tried my advice as mentioned above?
I hope this has been of assistance to you.