Tough to say what the issue could be. The cap or rotor could be corroded, grounds corroded, wires cracked. It's hard to imagine the coil or pickup coil going bad from sitting, it's possible. I'd started by checking grounds and connections for corrosion or bad wires. Check the coil for any visible cracks or damage. A mouse could have got in somewhere too and chewed stuff up. Ogres cave link at the top of the page has lots of good info that could help.
Also, for a car that has sat for so long give it a good look over before hitting the road. A particular fire hazard to check for is the heater fan resistor.http://www.fiero.nl/forum/A...130314-2-120744.html
Post updates as you troubleshoot so we can give better answers.