Coil pack wiring connectors

Hello, that brown/gray wire does power all the coils, as well as the Fuel Injectors. It comes from Fuse # 23 (15Amp) in the fuse panel in the engine compartment. The diagram below will show you there is a splice pack to check. Where the wire comes together and goes out to the Capacitor. Thats where you need to check and see if there is an issue with corrosion or other broken wires, even a small pin hole is a wire can cause a lot of corrosion inside a wire. It can infect feet of a wire like an infection. It can end up being all green and corroded inside. So, if the wire had some glue on there, someone else would have been in there trying to fix something and didn't do it correctly. I'll post the wiring diagrams below for you, if you find more corrosion and/or broken wires, the best thing is to fix them correctly, so this doesn't happen again. If you have to replace a section of wire. Buy the heat shrink connectors, these connectors when heated will shrink around the wire and prevent any moisture from getting inside. I will post a picture of them in just a minute.
These yellow ones are for a bit larger wire size, you will probably need the blue ones. After you use these to connect wires together, heat them lightly, don't overheat them, just enough so you see them seal around the wire. A heat gun is best, but you can get away with just using a lighter if you go easy on them.

https://www.2carpros.com/articles/how-to-check-wiring

https://www.2carpros.com/articles/how-a-car-electrical-system-works

Yes, they all tie together at the point where the Ignition Coil Capacitor meets up. The capacitor is that little square looking thing that is bolted to the ignition coil pack. It's a one wire device. No I wouldn't replace the whole harness, you'll be there forever doing that. I will go out and take a picture of my capacitor on my truck and post it in a minute for you. Can you follow the wiring diagram, okay?

Here's the splice, its S104 circled in purple. Thats where the 4 wires for the coils meet up.
All of these brown/grey wires are on the same circuit. The dotted line just means they're attached together.

Do you have the brown/grey wire? What I circled is where the splice is for those brown/grey wires. It branches off there to each coil and to the coil capacitor. What exactly did you take apart? Where I circled in purple is the wiring harness, it will be wrapped up in a plastic shielding. Inside of that is where these wires splice together. There's no need to run wires from anywhere else. That wire powers the Fuel Injectors and Ignition Coils. If you can take a picture of what you have going on there so I can get a better idea of what you're asking. I'm not sure what you really did to begin with.
I didn't get any photos. You should be able to post pictures here.

Okay, so someone before you may have replaced the coil power feeds is what you're saying. I went back to your original post. But yes, that wire that feeds the #1 coil also feeds the other 3. It will be the same wire on each connector for the coils as the #1 coil. The other wire on each coil is a different color because that is the control wire for that coil going back to the ECM.
Sorry for the misunderstanding.

Sorry the picture of the engine was to give a general idea of the location of the splice. In your first picture it looks like someone has made a mess of the wiring harness. The third picture does look like the Capacitor.
So, the brown/grey wire that is powering the first coil, you can power the rest off of that wire. The Capacitor is on the same power wire as the Ignition Coils because it cuts down the noise on the circuit. The Ignition coils produce thousands of volts of electricity, so the capacitor absorbs a lot of the electrical noise that is produced on that circuit, without it you would hear the coils firing through the vehicles' electrical system and through the radio. It could also send high frequency signals that could distort signals from other sensors that the engine computer is monitoring. So that's the purpose of the Capacitor. Is your concern about how to splice the wires together? I can see it looks like quite a mess there.
I fear someone else has changed all the ignition coil plugs, is that what you think happened here?

Well, whatever that glued spot was on that wire is not the correct way to fix a wire and my concern would be corrosion building up inside the feed wire for those coils. All it takes is a pin hole in a wire and after 6months to a year you will have green corrosion inside that wire, and it just keeps going up right inside the wire. You are smart to replace part of that feed wire. I will put together a small example really quick to show you how I would fix this. It would be difficult to splice 5 wires together especially in that case they should be soldered together, then heat shrink wrapped. give me just a minute.

This connector is the one I showed you in the first picture up top. Notice on these connectors when the heat is applied the connector end shrinks down around the wire, and if you can see it, there is glue that comes out as well. These insulate the wires from weather and moisture. The yellow ones are the larger size, these are made by Dorman and I got them at my local AutoZone. I think without soldering this is the best way to repair the wiring you need to. You may want to replace the wire from the 1st coil where you have power but make sure the Capacitor is included in the circuit before the coils. I know you have a mess of wiring there, but just do your best to sort it out and be sure you only connect to that one Brown/Grey wire and run to the other coils from there.
the fourth coil looks like the end of the line for that power feed. Just be careful before cutting any other wires or anything. Be sure of what you're doing first. But making sure those wires are protected from moisture is extremely important or you will just run into more problems down the road. (No pun intended)
If you have any other questions just ask. Obviously if you were able to check for 12volts on that wire, you should be ok with this repair. The Capacitor should have the same color wire Brown/Grey running to it too hopefully, it's on the same circuit.

https://www.2carpros.com/articles/how-to-test-an-ignition-system

Sounds like it should, just make sure the Capacitor is before the coils in the circuit. Make the #4 coil last. Keep to the original design as much as possible. But your plan sounds okay.
You may not need to replace all the connectors, are all the power feeds to the coil's different colors? The only coil wires that should be different colors are the ones that control the coils going back to the ECM.
The connectors are heat shrink butt connectors, AutoZone or Advanced auto has them. Or your local parts store, just ask, tell them that's what you need.

Okay, if it's the inside wire, the power wire is same on all the coil connectors.