Thank you all for the suggestions. Yesterday (at the suggestion of local auto mechanic) I pulled all spark plug wires and coil wires, checked all for good crimps and condition of the wires and tested coil, all checked out OK. Them on the distributor checked points cleaned up contacts and checked gap. Reassembled all and started up motor an so far it is running great. No cutting out at idle. I wish I knew what the problem was. ?????????????? This next weekend I will be taking trucks on a job. I will report back if the problem starts again.