Cylinder 3 misfire after changing valve cover and spark plugs

[Vanguard]

I recently finished changing the valve cover gasket (again) and changed the spark plugs with it (105K) on my 2012 e70 XDrive35i.

I've changed the valve cover before, but this time did the plugs as they were slightly overdue. After I completed the work, I started it up and got a check engine light. I pulled the engine cover, found a couple of loose connections - cylinder 1 injector and air temperature sensor. After clearing the codes I went for a drive and everything was fine.

Came back after a short trip and went to take my wife to dinner for her birthday and the CEL was back with a misfire on cylinder 3. So far I've done the following-

1. Rechecked the wiring and plugs to make sure everything is in place - no change
2. Swapped coils 1 and 3 - no change
3. Swapped spark plugs from 1 and 3 while returning coils to original position

After each step, I cleared the codes and restarted. After 3 everything was good for the first start. Ran it about 10 mins with no problems. As a double check I wiggled the wires for coil 3 and the problem came back. I inspected the wiring and didn't see any damaged wiring. Grounding wire seems good and tight. Ran the engine in a dark garage - no arcing visibile.

I was looking for a coil connector for the harness and noticed FCP sells the plug and a depin tool. Is this a common fix? Would it be better to find a new connector that splices into the harness?

My Foxwell is giving me the following codes:

2EE0 - Missfire. several cylinders : Fuel injection deactivation
2EEA - Misfire. Cylinder 3. Fuel injection deactivation
2EFE - Combustion misfires. several cylinders detected
2F01 - Misfire. Cylinder 3: detected

[Nanniepoo]

Unfortunately not much help with your particular situation, but I will say that from memory the ignition coil connectors were finicky on the V8 (not sure if they're the same). I think my first start after doing plugs and coils I had a misfire still and unseated-reseated that particular connection a couple times until I was happy, and it passed test run. But then a day or two later it started misfiring again on the way home. After addressing that particular connection (which I think was a different one), it still didn't feel good to me, but it's been fine for about a year and a half now.

[Attacking Mid]

Did you happen to use a little dielectric grease on the coils? I made that "mistake" recently on my wife's E83/N52 and had several brand new coils/plugs having misfires. After a few re-seats, I got it down to only one specific coil misfiring. I had to clean out the grease and re-treat the inner boot with baby powder as they come from the factory (per TIS). Haven't had an issue since.

AM.