No prob, B.
There's a vapor collection cannister; on my car it's down next to the radiator. That's where some oily junk might collect, but it's not really under any pressure.
The only breather hoses I'm aware of are at the PCV valve over by the intake- but that's pretty far away from the fuel filter. Again, this is how it is on my '97, the '91 might have a different layout. Is the '91 a turbo?
Sojuuk- when was the fuel filter last changed? I'm thinking more and more that it's just completely clogged up with crap...