So with the jumpers on, it starts and runs, right? Then it dies when the jumpers are pulled. Therefore there isn't enough juice to keep it running. Either the battery is dead as a doornail, and/or the alternator is not charging.

The former is an easy check. Open the door and look at the dome light while trying to start. (no jumpers) If the light goes way dim, very low battery.

The latter is also an easy check. Look at the back of the alternator for a thin red wire attached to a spade lug. There's a fat one, too. The thin one must be connected right, and not grounded anywhere, for the alternator to charge. Are the warning lights working right? All on in Position II, all out when engine is running?

Look at the gray harness connector mounted on the firewall. The wires coming out are subject to the very common crumbling insulation problem. Are any of them showing bare copper? That thin red one is one of those.

Post back with what you find.

Good Luck,

Bob

:>)