Still reading open neutral after restoring power to lights and outlets

Let me show you something I filmed a while ago to demonstrate this kind of thing:

https://www.youtube.com/watch?v=89Zl0Hrgd1Y

The outlet in the video has zero outward indications anything was wrong with it. How did I discover it? By accident - touching a lamp cord. It only flickered one time - and I could not make it repeat until I spent 10 minutes wiggling the tester in it. I filmed it precisely for demonstration on these online forums to people that outlets do indeed wear out, and fail internally.

After that I went to Lowes and bought 30 of them, turned off all power, then started replacing them one at a time. This was a new-to-us home with no furniture in it. I got to where I could replace an outlet in less than 10 minutes. Once I used up the 30 I bought more. Not only does it make the place safer I could use the new outlets that prevent children from inserting objects into the outlet in the bedrooms.

Stab-backs into outlets are known to be troublemakers. They are used for speed of building assembly. This outlet in the video WAS NOT a stab-back. Without actually being at your house and doing the troubleshooting myself I cannot be sure but it seems fairly obvious your outlets are being used as junctions and you have one that is mechanically broken. They can fail internally, just as my video shows. I would replace every one on the circuit and buy the better quality ones and assuming you have enough wire length, take the time to insert a pin to release the stab back, pull it out, bend the wire into a hook and screw it on to the new outlet. You are not building a house on the clock here and can do the job right. You can also take the time to align the outlet with the floor so it's nice and square. I always think it is such a hack job when I see a crooked outlet or switch.

Also, you say you have an open neutral yet the outlets are working? That does not make sense. The neutral must be present in a 120v outlet for it to work. Possibly you mean you have an open GROUND? Use your multimeter on the AC section and check to make absolutely sure there is potential both between the black and white wire, and the black wire and green wire. If you do not see 120v between black and green you have a dangerous situation. If you have potential between white and green, and not black and green, you also have an incorrect and in my view, dangerous situation as you have a pair reversal somewhere.

You found a classic case of why backstabs are considered bad news by many electricians. When you pulled the receptacles out the connection was temporarily reconnected and the lighting is working again. As we don’t know if everything was proper to start with but is functioning now I can tell you this will normally happen again and eventually burn the wire off at the weak point. I would suggest checking each receptacle working back towards the supply or service and if one shows properly connected and the next one away shows wrong the problem is one of those 2 points and a device can be connecting ground and neutral down stream making them work or many other reasons.

If you plan to continue using a space heater I would suggest moving to the screw connectors or pigtails as this usually happens again with a heavy load.

The point of failure is at the last working or first non working receptacle or splice. If this bedroom has a common wall with another don’t forget there could be a receptacle on the other side of the wall in that circuit.

I pulled the stab back connections, pushed them in firmly,

Can't do that. Backstab connections are ONE TIME use. Whatever you did to pull the wires out, that has "sprung the spring" and it no longer has the original gripping strength. It is not capable of holding the wire again.

If they ever were, LOL.

But this is the crux of the problem with backstabs. You need to inspect the wire connections to see if they are intact. But you can't inspect a backstab because it's buried in plastic. The best you can do is (destructively) wrest the wires out as you did, and look for arcing damage on the wires.

"But wait. If I pull the wire out, how do I signal to myself (and the next person) they should never use that hole again?" For most of us it's simple: never use any backstab hole in any case, ever. They're not worth the trouble they create. However the second way is simply replace the whole receptacle - we are dealing with a commodity "builder grade" receptacle that costs 60 cents. Third is to shove a bare stub of #14 wire in the hole and clip it off flush. Don't use "spare" length from the wire coming from the walls; that length is precious - it must be >=6" from the end of sheath or it's a code violation and must be re-pulled.

The "spec-grade" receptacles ($3) do not use backstabs, but use a feature we call "screw-and-clamp" where you back-wire, but tighten the screws to clamp them! These accept 2 wires under each screw.

Where you see 3 wires landing on a side, it may simply be a 3-way wire connection - supply and two onward cables. That can be pigtailed. But you should also check the breakaway "tabs" to see if the receptacle has been split. Here's more on watching out for that.