Check Engine light on since 2013?

Hello, so for this year being its age, the service information wiring diagrams are not very helpful, but with all these sensors alone setting codes, the Intake air temp sensor (IAT), Coolant temp sensor (ECT), and the Barometric pressure sensor most likely all share the same 5 volt reference voltage regulator inside the ECM. When it comes to thermistor's which is what the IAT sensor and ECT sensor are, to check the 5-volt feed, the sensor needs to be unplugged to check for a full 5-volt feed. Key On, Engine Off, one of the two wires to the sensor should read 5-volts, if for some reason that 5-volt feed is shorted out, whether its inside the ECM or another sensor causing it, it will cause those sensors not to read as an input to the ECM.

Service info does provide the pinout for the ECM connector which, after you check at the sensors for its 5-volt, if something doesn't look right, you would check it at the ECM. It sounds like the "new" ECM you installed, being a remanufactured computer, might have come with problems, many rebuilds do. But this is a very basic setup except that you can't get the best live engine data on a scan tool being that this is an OBD1 system, newer systems from 1996 and newer are all OBD2 with advanced scan tool options.
I would start by checking the IAT sensor unplugged, if 5 volts is there, plug it back in and check the ECT unplugged, I say thing because if either the IAT is shorted out the 5 volts, or the ECT is shorted out, you won't know when checking the next sensor if the previous sensor is still unplugged during testing, if that makes sense.
I see in the ECM pinout diagram there is only 1 sensor 5volt reference feed for them all, so that's something to check.

I would also do a voltage drop test on the ECM grounds. If this computer has a temperature related issue, such as a cracked solder joint inside, you will end up with thermal type issues like this. And unfortunately checking at the ECM connector will not tell you if there's a cracked solder joint on the circuit board.
But in some cases, a bad ECM ground can cause the 5volt reference to rise to a higher voltage, bad grounds can cause all kinds of very difficult issues, especially when they are internal to the ECM itself.
But I will post the ECM pinout for its connector so you can check the voltage readings at it if necessary.

To do a voltage drop test, for example you are measuring from Positive to Positive, so if checking for voltage drop from the Battery + to the ECM B+ feed, you would have a meter set to DC volts and check from Battery + (positive) to the wire that feeds the ECM B+ and with the vehicle running it should be as close to 0volts as possible, there will be a little bit but it shouldn't be over 0.5volt at its extreme max, so when the vehicle is hot and some electrical loads are on such as headlights, etc.

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

https://www.2carpros.com/articles/how-to-use-a-test-light-circuit-tester

https://www.2carpros.com/articles/everything-goes-dead-when-engine-is-cranked

These are the ECM connector pinouts, there are additional voltage values for each pin I will post next, since this doesn't seem to list all pins.

These are the voltage values you should read with the key on, and then engine running.

This is a simplified voltage drop testing diagram, excuse my artwork.

The wiring diagrams for this year are very difficult to read and were hidden on the transmission wiring diagrams, but the Intake Air Temp sensor and the Barometric Pressure sensor are built into the Mass Air Flow sensor which is part of the air filter housing, so you should see a 5 or 6 wire connector going to it.
Sorry for the delay, hopefully these diagrams are easily understood, if you have any questions on testing, just ask, It sounds like a part of the Mass air flow sensor (volume air flow sensor) may have stopped working, or there may be some corroded connectors in between the sensors and the ECM (engine computer). Since it's only these 4 sensors setting codes and not others. There are other sensors that work off the 5volt reference that appear to not be setting any codes, such as the Mass air flow sensor, but other sensors built into that one component are setting codes, so it can be tricky.
I would start by verifying the 5volt feeds wires to the sensor in the air box, at its connector. I've tried to add as many details as possible to the wiring diagrams, but I know this testing can be difficult if you're not familiar with it.
When checking for any of these 5volt feeds, use Battery negative as your meter ground (black lead) and the red lead for reading the voltage levels with the Key On, engine off to begin with. I will try to locate the Coolant temperature sensor as well.

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

Here is the location for the coolant temperature sensor, there looks to be another temperature switch by it that is probably just a one wire temperature switch and not the sensor setting the code.

Hello, I'm sorry for the delay, I am in North Carolina just east of where the storm hit and we're sending supplies to people we know in Asheville, I do apologize for not getting back to you sooner.
It does look like some of those readings are off, I will have to pull up the file on your vehicle again and review the diagram again, but with thermistor components such as the IAT and ECT, the ECM sends out 5-volts to the sensor and the ECM monitors that 5volts internally for any change in voltage. And because the thermistor is basically a resistor that changes resistance with temperature fluctuations, higher or lower temperatures will cause the sensor to vary the voltage the ECM is seeing on the monitoring circuit through a resistor. The resistor helps also if the 5volt ref happens to be shorted to ground. It's a protection device. Let me look over your testing results really quick.

Okay, so on the idle speed motor, pin 5 is the motor's position signal wire, it should not be just 0 volts, you notice how it is in between pin 3 and pin 6, here's some resistance checks to do on the position sensor. You're missing the motor's position signal to the ECM.

This is additional testing for Code 13, I'm going to post these, because I'm seeing some service info that varies a lot.

This is for Code 15, the ISC motor position sensor's resistance value is actually only 4000-6000 Ohms.

This is Code 21 ECT.

But Code 23 in service info is not listed as Baro sensor, it is stating a camshaft position fault. The Barometric pressure sensor fault is listed as Code 25 (diagram 3). I don't know if that was a scan tool reading the code incorrectly, the camshaft and crankshaft position sensors are inside the Distributor on this vehicle, and if they were not functioning, you would have a crank no start condition.

I'm not surprised if some of the wire colors are not correct, this is very old service information. I'm going to post this info first, but I'm looking over your readings you took at the ECM again, it states 83f degrees out, but the IAT sensor is at 1.1v and the ECT is the same These are Key On engine Off readings I assume,

But the Pin 19 is the Throttle Position sensor that's the incorrect sensor, we need ECM Pin 17 that is the Idle Speed motor position. If Pin 17 at the ECM is reading 0volts like it is at the idle speed motor, that's why the code is setting.

Some of these wire colors will fade over the years and it can be difficult to tell what color they are. So for A-35 we will have to go with wire/pin location in the connector.
It might also be that, when disconnected they are showing the connector face (so the wiring harness side of the sensor's circuit), looking at the female pins of the connector.

While checking the Idle Speed Control motor position sensor (diagram 1 below) you didn'tt have 4000-6000 Ohms (4k-6k) across pins 2 and 3?
We just need to know if the sensor is open circuit inside (diagram 2). I think you were testing the harness side of the circuit, when unplugging it, check the male pins inside the sensor side, not the harness side.

We need to check each sensor that is setting a code for an open circuit internally first, If that reads ok, then we move on.
So its the same with the coolant temperature sensor, unplug the two wire connector, move it aside and measure the sensors male pins. Sorry I know these wiring diagrams are not the best by any means.

Thats why in the 3rd diagram when checking pin 3 you had 0 ohms because its the sensors ground wire. But since these diagrams are so old, we would load test wires these days and only use continuity testing to see if there was a short to ground.
The low voltage is a concern though, diagram 4 and 5 are for the IAT 5v reference at the sensor connector(unplugged) and then the ECM connector(plugged in still) back probed.

Those low voltages will cause incorrect readings, and starting issues if the ECT has low voltage because the coolant temp sensor is the main sensor the ECM looks at during a cold start.

This is the code setting criteria for Code 13 IAT. With the engine running, readings at ECM pin 8 at 1.7volts looks normal, or within range around 104f degrees, which is okay.

The next is Code 21 ECT, running at 0.4volts is around 180f degrees, which looks normal too,
So, this might be an intermittent issue with this ECM, obviously you're getting some lower-than-normal 5v reference readings. But Pin 17 needs to be checked to verify this code 15 ISC motor position,
But I would recheck the pin 8 and pin 20 with both the IAT and ECT sensors unplugged at the same time and see if the full 5volts comes back,

The Code 23, we will have to check last, because it's listed as Cam sensor,
But you can see the code setting criteria in the diagrams 1 and 2 below, it's possible the ECM circuit board may be having an issue either when hot or cold. And that's when these codes are setting, these older ECMs are also pretty easy to repair if this is a soldering or corrosion issue on the circuit board. I've repaired them in the past, due to broken solder traces and such.

The 11.4volts on Pin 4 of the ISC motor position sensor is incorrect unless service info is wrong on what voltage is supposed to be on that wire, because it's the position sensor setting the code, and we need to know if that is open circuit or not inside the sensor, if Pin 5 was checked with the sensor unplugged you would read nothing, we need to resistance value on pins 2 and 3. I'll post that again (diagram 5).

Well, don't be too hard on yourself, the crank sensor and cam sensor are inside the Distributor, along with the ignition coil and a power transistor that triggers the coil on and off. A common symptom of a bad crank or cam sensor is a hot or cold stalling issue, more on the hot side like you are experiencing, when the sensor gets hot, it expands and if there is a wire (winding) in the crank or cam sensor that is touching when it's cold, it will open up when hot, and there's your stalling issue. It will cool down and start to function again.
I would clear the codes out completely and see what ones come back now, since it's been so many years.

As for checking Pin 8 and 20 at the ECM, Pin 8 is the Intake Air Temp sensor, Pin 20 is the ECTemp sensor. I would unplug them both at the sensor, then key On, engine Off, see if the full 5 volts comes back on both wires,

There might be more than one 5-volt regulator inside the ECM, it's unlikely on an old computer like this, but who knows.

Now depending on how bad the damage is to the connector of the idle motor sensor, if there are wires that are shorting together, meaning the pins inside the connector are touching in any way, that might be the issue for all these problems, the damaged connector is most likely going to be the cause of the Code 15.

I'll explain; if this ECM has just one 5-volt supply internally that it uses for all the sensors in the vehicle, and if the idle motor position sensor connector is shorting out the 5-volts to ground or to another wire that's pulling it low, such as the lower voltage you were reading, that is going to affect multiple sensors, and if it is an intermittent issue where the wire is shorting out, then it's not, then it is, you can see the turmoil that will cause.

Pin 23 and 13 of the ECM are supposed to be a 5volt reference for the sensors, you can see it in the diagram that goes to the idle motor position sensor.
It might not be the Distributor that's getting hot and causing the stall though, if the new one has the same symptoms, it might be the ECM getting hot and shutting down the vehicle.

When it shuts down when hot, turn the key On and see if the Check Engine light comes on for a few seconds, if it doesn't that indicates the ECM is probably not powering up, also check the 5volt Ref when its stalls out hot, Pin 23. I'll bet it will be missing or low voltage.

A bad ECM is difficult to diagnose. Sorry, this is all so complicated, it's because we are dealing with multiple codes, but erase them if possible and see what comes back, if you don't have a scan tool you can ***disconnect the battery for at least 10 seconds should clear the codes.

Reading codes on this system you will need a scan tool with an OBD1 adapter to it. (3rd diagram shows how they want you to read codes without a scan tool which requires an Analog multimeter, which I don't even know where you would get one that old anymore.)

Can you take a picture of the connector for the idle motor sensor so I can see the damage to it?