1995 Jaguar XJ6 gas smells from trunk

On your 95 XJ6 the fuel cap is below the drivers side rear window, in front of the trunk, laying flat. Right? Same as mine. If you filled the tank before this and spilled any gas outside of the tank, there is a line running from this resevoir to underneath the car, sort of towards the backseats, but underneath the tank in the trunk. It might have been gas from this runoff line? Just a thought you might want to check out if it isn't an actual leak.

I can share my findings with smelly trunk on Jaguar XJS', which may help your case. The problem with this issue is the design. All fuel lines are made of rubber and these are not totally sealed to gas vapors. On top, all of these connections are in the trunk. The problem can be partially solved using a fuel sniffer, locating the porous hoses and replacing the worse ones with the best quality hoses you can buy. Direct OEM replacement is not a solution. The long hose coming from the left of the tank down to the surge tank is the worst offender. There are also vapor leaks through the fuel sending unit. Assemble the gasket with silicone sealant on both side of the gasket. Ideally, all hoses should be replaced with steel lines, but this is a major undertaking.
A fuel sniffer will show you that gas vapor leaks are found all over the system. It is sad that Jaguar does not offer a sound solution for this serious issue.