Intake air control valve?

The distributor is known to be good, it was working when it was removed, I bought a spare one in case of a breakdown beside the road. I put the new one on for warranty reasons.
I like keeping extra parts for my truck, like alternators and distributors and so on.
I know how to install it. I have some knowledge in vehicle repair.
The truck was quitting on me again today, it's like you turn the key off at times but sometimes it gradually starts dropping the idling then all at once it jumps to zero miles per hour.
The coil is inside of the distributor and I think the cam shaft position sensor is in there also.
I'll try to get that distributor on in the next few days, I have a friend that will do it for me but I'll watch him to make sure. Let you know how it goes. Thanks

I forgot to tell you that I checked the resistance of the third injector coil and it was 8.5 ohms, the fourth one is hard to get to but I will check it sometime. I think Nissan says that the coil resistance should be 10-14 at 77 degrees Fahrenheit.
Do you think that maybe one or more of my injectors might be sticking or something similar to that? I will change out my distributors and let you know the results. The IACV that I replaced the wiring metal connectors were smaller in length where it goes into the plug in, do you think it might be possible that the connection isn't what it should be? This IACV when bad gives the code P0505, my truck had given me that code at the start but that code has not came back with this new one installed. Could it be possible that an intermittent connection at this IACV could be causing this problem or would it put the code P0505 if this connection wasn't perfect? I appreciate all your help and it will be figured out, just don't give up on me. Thank you

The distributor has been put in and it's still doing the same thing. I noticed that when my headlights are on and the heater is blowing my voltage drops( idling ) down to a little over 12 volts, 12.2. 12.3, 12.4 but if I give it gas it shows it charging good. When I drive I can feel a miss in engine.
I might be getting an intermittent connection at the IACV from the short connectors, not 100% sure of that. I listened to the injectors with a pipe and they all sounded the same, no difference in sound so I assume they're okay.
I'm going to measure the inside where the connectors are to see if they are long enough to make the correct fit for a good connection. Let you know the outcome. The IACV code P0505 has not returned but it acts like it did when the valve code came on like the air flow isn't correct for gas mixture.
When I turn the AC on it doesn't do that, I will attempt to run the air tomorrow and see again. Have a good night.

The fuel pressures are good. I have a fuel gauge connected at all times showing the correct pressure. I refilled the gas tank the other day. Prior to this I put a small bottle of fuel treatment in the tank.

It might still be my IACV-AAC, Since it's an aftermarket, truck ran a little better today,
Reset the IAC valve pintle position by performing the following:
Depress the accelerator pedal slightly.
Start the engine and run for 5 seconds.
Turn the ignition switch to the "off" position for 10 seconds.
Restart the engine and check for proper idle operation.
Www. Autozone. Com †ELECTRONIC-ENGINE-CONTROLS †Idle-Air-.
Idle Air Control (IAC) Valve Repair Guide - Repair Guides
Search for: How do I reset my idle air control valve?
How many ohms should a IAC valve have?
Using an ohmmeter, measure the resistance between pins 1 and 2 on the IAC valve. Resistance should be 10-14 ohms. If resistance is okay, proceed to the next step. If resistance is out of range, replace the IAC and retest.

Yes, from Ebay, I drove it again this evening, it seems to be doing a little better than it was, it only attempted to quit one time. I think that the IACV might be a little stiff since it's new & needs a little time to break in or it might not be up to par compared to the ones Nissan sells, who knows.
I'm trying to be patient with it for a little while to see if it might finally start working correctly. I'm still confused on whether the two wires on the IACV have a positive and the other is negative. Once the male connectors are in the plug in it's just about impossible to remove them without totally tearing the male plug into where it's not reusable again. I did the first one that I removed that way, they may have a special tool to remove them.

Thanks for your answers.

I've refilled the gas tank and put a bottle of Sea Foam in the tank, it seems like it might be running a little better for now but I will run it tonight and see what happens at idle and driving it around a little bit.
The original distributor ( inside clean ) that I put back in it is an Hitachi, the one that came with the truck.
The air filter is clean, timing chain and gears are not to old, air filter is good and clean, gas filter hasn't been on that long so mostly everything should be alright there.
I ordered a PVC valve to put on since I'm probably saying that it has never been changed, I know I haven't since I've owned it for about 10 or more years. It will be a few days before I get the PVC, ordered online.
It's hidden down behind the alternator between it and the oil filter and it screws in with a hose attaching to it. Will let you know the results. Thanks

It's not fixed yet, drove it tonight doing about the same thing but it isn't quitting as much but it did once tonight. I looked on Ebay for a mounting throttle body gasket and emailed a seller about if the one he had advertised would fit this truck and haven't heard from the seller yet.
It's been raining here and more tomorrow. I'm going to take the throttle body off again and use some liquid tape to put on the metal vacuum lines to make sure there's no leaks there, going to recheck each vacuum line for leaks. Sooner or later the problem will be resolved.
On the 2 wires that's on the IACV one of them has white letters on it, the plug in has the white on one of the wires but mine is not matching up to the one on the plug in, in other words this wire with the white letters is on the ground side of the plugin, would that matter? Should I attempt to switch these 2 wires out so the white stripe one is connected to the white striped one on the plugin connector. Are you out west, I live in Kentucky. Thanks for your answers.

Joe, be patient, received PCV valve just waiting for a warm day to put it on.

Joe, I didn't have anywhere to answer you on page 3 so I found a place on page 2. I interchanged the wires on the IACV and it did not help. The ebay seller told me they'd replace it if changing the wires didn't work. Installed PCV, did not fix it.

Joe, do you have any more thoughts on what my problem might be if this other IACV-AAC doesn't fix it? I haven't received it yet. I may have to buy an Hitachi brand if this one doesn't work. I know there is a heat sensor that is on this truck that will shut the truck off it the motor gets to hot but my truck is not over heating and I don't know where that switch might be located, do you have any idea where it might be?

No, I'm talking about a sensor that if you for example, get a water leak and your truck starts overheating it will automatically shut my truck down to keep from burning the motor up.
I had that to happen one time, one of my radiator hoses blew off and my truck quit on me when it got real hot and would not start back until it cooled off and I put some water in it. I don't know where that sensor is, do you?