Just to update this thread. I had a fuel smell of undetermined origin on and off for awhile. Finally there was visible fuel dripping from the tank towards the drivers side.
We dropped the tank and there was corrosion evident on the hard fuel lines on top of the tank. I replaced all fuel lines and the fill line as well as the fitting for it into the tank was suspect.
I think that area on top of the fuel tank , under the floor is a problem area for moisture/salt to get to and sit there. I'm in NJ, 180k Miles., owned since new.
Just a heads up if anyone smells fuel and can't figure out where it's coming from.