Engine quits after a short warmup?

Hello, have you checked for spark when this stall out happens? And you have fuel pressure when the fuel pump relay is chattering away like that? Sounds like you may be losing power to the fuel pump relay or some voltage, if there's a voltage drop through the PCM power relay and there's only 6 volts, for example getting to the fuel pump relay. And it's not enough to keep the relay contacts closed. The fuel pump relay gets power from the PCM relay for its control side. I'll post a diagram. But check the under side of that engine compartment fuse box, they get corroded underneath, and the pins will eventually rot right off and break. If you don't find any corrosion at all, pull the PCM relay and with the key On, 2 of the 4 pins where the relay sits should have 12-volts on them, that PCM relay is a power side-controlled relay. So, the ignition switch sends power to that PCM relay and it in turn sends power to the fuel pump relay, the PCM, the transmission, etc. But use a basic multimeter set on dc volts and when the stall occurs check that you have 2 powered up pins, they will be marked on the diagrams I'll post.
But corrosion is common on these older Fords under the fuse panels, especially the ones exposed to the elements. Let us know what you find. I'll post some other information as well.
Just refresh this post every once and awhile in case there's new information posted for you.
If you're losing ignition spark, you may have a failing ignition module, very common on these. So, find out what you are losing when it stalls out,
Some of the ignition modules on these older vehicles are mounted either on the side of the Distributor or on the body in the engine compartment.
Here's a great video to watch, it's on the older Ford ignition systems. He shows some really simple checks you can do with a test light to check for spark and ignition coil control.

https://www.youtube.com/watch?v=llYFDC5-sa0&list=PLAFYVCyenqcoRt2bJPI4vcee2w_1Y3fkm&index=4

https://www.2carpros.com/articles/how-to-use-a-voltmeter

https://www.2carpros.com/articles/how-to-check-for-ignition-spark