What's wrong with this '95 Ford econoline

Idles rough, seems to drive OK down the road for 30 miles then stalls at a stop sign, and then cranks hard as if the battery is low. But the battery has a charge and the headlights are bright. Once cool, it starts again fine. I've replaced or bench tested almost all the usual suspects. (Including the infamous ICM, aware of the "parts number mixup"). My current list of suspects:

1.) The 175 psi cylinder compression is typical for so old a vehicle but out of spec for ethanol gasoline.

2.) The fuel pump is overpressurizing at idle and opening a pressure relief valve, causing stumbling.

3.) The replaced coil is a piece of junk and I need to get a more expensive one if I expect it to work.

4.) Can the inertia switch do this, the thing you unplug to depressurize the fuel system?

Needs a tune-up.