1986 F150 5.0 EFI will not run

This is a long post but I want to describe everything I know about this problem truck. I have a 1986 Ford F150 XL 5.0 EFI 2wd 116” wb, 4 speed manual trans with 50,700 original miles.   The truck sat for many years under a carport in Virginia.   I have all the service records from the original purchase.   
The truck wouldn’t run long enough to drive on the trailer.   My first thought was a sour fuel problem.  The gas gage did not work.   I was able to determine the gage was NOT defective.   So I ordered a new in-tank fuel pump/sender unit assy, the canister fuel filter and tank.  The pump and sender were totally shot and needed replacement.  The tank was rusted so I replaced it also.  
After installing these components the gas gage worked but the engine would run for a few minutes and stall.  
Even though it would run, I couldn’t accelerate hard; very bad hesitation.   It behaved like it was not getting fuel.  I ran an OBD1 diagnostic test and the ignition module came up bad, Code 18.   I replaced it with a Motorcraft module and the truck started but as soon as it began to warm up it would die again.  The module didn’t help with the hesitation or solve my problem.  What I learned was it wasn’t the ignition module; it was a bad connection at the SPOUT connector.  I was able to set base timing at 10 DBTDC.  And the self test verified the distributor ignition module advancing to 30DBTDC as per the spec.   A vacuum gage at the intake plenum was steady at 25” of mercury.  The alternator was 14+ volts at idle at the battery.  But the truck would stall out after the high idle would settle down.  
I put a fuel tester gage on the fuel rail and it would hold steady at 30psi at high idle.    When the idle began to fall off as the engine warmed up the the gage would drop eventually to about 8 PSI and then the truck would stall.    It wouldn’t re-start until waiting 10-15 minutes.  I installed new in-line HP fuel pump.  I suspected maybe a bad fuel regulator but when the engine would stall I noticed whatever pressure was on that gage at the time it stalled remained on the gage.  The pressure held until I manually relieved it.  I do have a new fuel regulator that I will install.  I also bypassed the inertia switch with a jumper wire to eliminate any interference with the fuel circuit.  
So I’m going to finish with the fuel side.   I pulled all the injectors and will have them serviced-tested. This way I’ll have a clean fuel and a good delivery system from the tank to the intake manifold.  I don’t think the injectors are gonna be the problem.  
I suspect something else is going on, possibly an engine temperature sensor issue.  Recall I had to wait about 10-15 minutes before it would start again.  
Is there a history of engine temperature sensors causing the symptoms I’m having?   I don’t want to throw anymore unnecessary parts at the truck.   I already feel foolish buying parts that didn’t fix the problem.   The fuel components I’m okay with because the truck sat for so long with nasty fuel in it. 
Any info/advice is much appreciated.   
Thanks
Dennis

You may need to check for an issue with the fuel system. The part where you stated the fuel pressure drops then stalls has me wondering If it is a cause or a result. An amperage waveform would give us direction on whether it is the command, the pump itself or possibly a switching valve if it is dual tank

The truck has just one tank. My ODB 1 diagnostic tool requires the truck to run to check dynamic performance however the truck won’t run long enough to run any dynamic test except the advanced timing test, which the truck passes. By the time the tester instructs me to mash the accelerator hard to test the emission sensors, the truck stalls out. Therefore I don’t know if the pump is the cause of my problem or the effect from the ECM responding to some other sensor.