Do you have a wiring diagram and / or service manual? I’ve got some stuff from that era that I can post, but it’s for the Taurus / Sable. Hopefully it will be the same.
The ignition system is connected to the EEC-IV computer. You may find a code stored, I can post the instructions for pulling those if you need it. Does your dash have the Service Engine Soon light? (The earliest Fords with the EEC-IV didn’t). If not, you’ll need a voltmeter too.
I recommend this book for anyone with a pre-OBD II Ford;
Ford Fuel Injection & Electronic Engine Control: How to Understand, Service, and Modify : All EEC-IV Systems on Ford, Lincoln, Mercury Cars and Light Trucks 1988-1993 [Charles O Probst] on Amazon.com. *FREE* shipping on qualifying offers. Ford Fuel Injection & Electronic Engine Control: How to...
www.amazon.com
Also available from the publisher. You might shop around, but this book will teach you everything you’ll ever need to know about fuel injection, a lot of it still applies today.
As a side note, there is also a similar book for 1980-1987 Fords, with the same title and publisher.