My black 94 does this too. It seems like it's flooded, I'm thinking maybe it's a leaky injector(s)? It only does it, like you say, after it sits for about 15 minutes after it has been driven.
It starts fine cold, or if I shut it off to run into a store then restart it. It runs fine otherwise.
I don't often start it after it sits for 15 minutes, and it's my winter beater, so I never really looked into it.