I have a 1986 Riviera that will randomly die out after getting to operating temperature. Sometimes it will fire right back up and drive just fine for a while. Other times it does start right back up, when this has happened I have tested the spark on top of the coils and I get no spark for a little bit. I was thinking it could be the ignition control module so i replaced it but still same problem. What else could cause a problem like this?
Also check for a defective magnetic pick-up in the distributor.
Tester
Its Distributor less Ignition System there are 3 coil pack that sit on top of the ignition control module
In that case the problem might be with the crankshaft position sensor.
Tester