The cooling fan thermal switch failed.
The exhaust manifold gaskets leaked.
The headlight motor bushings needed replacement.
The ignition switch had a short and needed replacement.
Other than routine maintenance items (wear & tear), no additional major problems.
The Fiero is not a car I would consider taking on a long road trip (minimal trunk space, tight cabin, etc..). However, I absolutely love it for short blasts just for the sheer fun of driving.
I own a Cadillac Seville and a Mercedes-Benz for everything else, but drive the Fiero whenever I can justify it. I currently own 3 and would jump at the chance to purchase a new one were Pontiac to bring the car back.
It's a good thing you caught that ignition switch short. These car's were known for fires. Since you have a Cad and a Mercy, you have the money to repair the Fiero when it blows up on you. My advice, sell it while you still have hands.
Only the first year (1984) 4cyl were known for fires. They fixed the problem. Get your facts straight.