Update - problem solved - replaced the battery.
Yesterday we had below zero temps and it still started fine so I am calling it fixed. The fact that I could get a spark on all plug wires while cranking, had proper fuel pressure, and the camshafts were turning, all were puzzling. The ignition module checked out fine. New plugs. Relatively new plug wires. Apparently even with jumper cables on I wasn't able to maintain enough voltage for the computer to operate properly. Yes, the engine would crank over slowly, but on a 12 °F day it started once and ran fine until I shut it off. Then it would not restart. Crank, yes. Fire off, no. The only difference in that time that it started and other attempts was that the battery charger had been on high charge for about 4 hours.
Maybe this will save someone else from going through all that I had to go through to figure it out.
WT
Friday, January 16th, 2009 AT 12:41 PM