My 95 Ford e350 starts and will run for 20 min and then stalls and won't restart
Good indication of low fuel pressure, check fuel pressure, it should be 30 to 45 psi. threw gage, and should be over 45 psi. at a dead head check.
You need to find out if the stalling is fuel or spark, but going out on a limb here this sounds like the typical Ford ignition module failure, runs good cold but when it warms up it quits running until it cools off then it will start up. See pic.
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