Booster Vac Line gets Full Manifold Vacuum. If the engine even runs should have very high idle and maybe setting DTC for IAC problems.
Depending on year of Fiero... 3/8" 84-86, 1/2" 87-88 hoses and hose fitting.
84-86 uses filter in engine bay. No flow then check for blocked filter.
See my Cave, Brake Service
Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
The Ogre's Fiero Cave (It's also at the top and bottom of every forum page...)