I started the Mustang to warm it up and it died after about two minutes. I tried to start it again but it would not start. I immediately started troubleshooting parts as I know from past experience this intermitent problem does not last long.
I disconnected a spark plug wire (#5 cylinder) and connected it to a test tool. The test tool connects to a ground and has a small, adjustable gap. If the ingition is working, you can see the spark jump across the gap. This was not occurring so I know the problem is ignition related.
I then grabbed the spare coil from the trunk and installed it in the car. I left the spark plug tool in place and tried to start the car. I still had no luck starting the car and no spark. The only thing left are the components inside the distributor (primarily the Ignitor I).
I was not sure how to check the Ignitor. After a few minutes, I tried to start the car and it started just fine. I searched the internet and found the following image which contains the test procedure for an Ignitor. If I can get this to happen again, I'll test the Ignitor.