Thanks everybody.
I'll take that award Wedgy!
What broke? Well, that's the $64 question. And it took a LOT more than $64 to find out.
The short answer is, we don't know exactly. Something in the ignition system. Not fuel pump. That's been done before, according to the stack of receipts Dad had kept. And it was good.
The long answer? One of the details I didn't provide in the already too long story above, was that after it died and would not re-start (crank only)....this was very hot conditions. Hot day, just off a run down the highway, idling at a light. After she sat for a 1/2 hour, and the tow driver was ready to pull her up on the flatbed, the front tires were maybe 6-8 foot away from the edge of the ramp. He asked my to try it one time, to see if I could pull it forward those few feet. And wouldn't you know the damn thing started. So something got too hot. Had a solid check engine light, so a stored code.
When the shop called me, they could see that much under the bonnet was original....20 years old. And they wanted to go to town. They offered me two options, the full boat including every maintenance item that had never been done as far as THEY knew, including a coolant flush, belt, tensioner, etc. This would have cost more than I paid for the van. Literally.
And all of this things had looked up to snuff at the shop back home that I have used for 20+ years.
After I backed them away from that cliff, we focused on doing everything in the ignition system. Crank sensor, coil, cap, rotor, module, distributor, plugs, etc. This cost a few hundred less than I paid for the van. It would be easy to be cynical and say they had me, and went all out to over-repair the van. And while I was not in a position to argue, I wasn't entirely against this approach. Since it started when cooled off, how would I know for SURE we'd fixed it until the long drive back to Detroit? Did I want to risk breaking down on the side of the highway on Tennessee or Kentucky, up in the mountains? All because I wanted to second guess the guy working on it? To save a few bucks?
I did not. So I gave them carte blanche to rebuild the ignition system. Now, I'm not trying to brag, or try to show off. MANY people in the auto industry and hobby know a LOT more than I do. But I do have a couple of automotive degrees, spent some time in a Chevy dealer, and many years as a contractor to GM here in Detroit. So I have some notion of what's going on.
My guess? I think it was the coil. While crank sensors can be intermittent, or fail when hot, in my experience, they are like a light bulb. When they fail, they fail. Obviously distributor (high voltage switch in GM speak for the L30/L31 engines) itself was not the issue, nor the plugs or wires, cap or rotor. Could have been the module, but I'm thinking coil. Why? Because of that slowly degrading gas mileage on the way down. Ran, but getting ever weaker. I could be full of it too, but whatever it was, we killed that fly with a sledgehammer.