lumina loses all power and dies

[oldude]

I have a 1993 Chevy Lumia 3.1 with 150,000 miles. I went to start the car and it didn't do anything. I turned the key again and it started. A couple of hrs later the car wouldn't start and there was no power at all. No lights, radio etc. I jumped started it, drove a couple of blocks and it loses all power and dies. I towed it home and tried to jump it but it would not start. I reached down to see if the neg batt cable was loose (it wasn't) and as soon as I touched the cable I heard a click. ( i assume the ECM). I turned the key and it started up. I pulled the batt and neg cable off had the batt checked. The batt tested good and the cable looks good. Got everything back together and took it down to have the alt checked. It checked out good also. The wife drove it yesterday and when she backed out of a parking space unto the street the car died. She said the dash lights flashed a couple of times and then it died. After turning the key 3 or 4 times it started and she drove it home. Any ideas what to look for? Was it the ECM that clicked or a relay?
Thanks for your help

[maxwedge]

Replace the cable.