5K Gas Smell on Shutdown

[Steve Sherman]

My 87 5KTQW has recently (for a month or so) been giving off a gasoline
smell after shutdown.  If I return to the car say 5 min after turning it
off, a gas smell is very noticible.  I've looked under the hood but no
obvious leaks anywhere.  And the smell is not present housr later or in
the morning before driving.

I was curious if anyone has any ideas of what to check or common places
for such a leak to come from

TIA