Alright guys, I hate making my first post a "please help" post, but I feel like I'm taking crazy pills right now.

Back story; I have a 2008 TL Type S AT with ~140,000 miles on it. About 2 weeks back I got the "gas cap loose" error message on the Nav system and the car had a rough idle. This went away the next time I started the car up and didn't think much of it. Drove a number of highway miles traveling for Thanksgiving, during which I received no CEL, power seemed normal, higway MPG was in line with what I've always gotten at 29.xx. However as we are closing out the drive home, stuff starts going sideways on me. Whenever I would come to a stop at a light while in drive, the idle became very very rough. Dropping to 450-500 rpms at times and on the verge of stalling out. However if I shifted the car into Neutral, rpms came back up and she idled just fine. I limp the car along home still with no CEL or major noticeable differences to how she drove with this Drive/Neutral combination. Drove on it for a couple of days to work, before I had the time to work on it, during which some days the car was fine, some days the rough idle would come up.

Current major issue, I decide this is most likely(or maybe just hopeful that) a spark plug issue and go about replacing the spark plugs. In and out, zero issues with 5 or the 6 plugs. They look a little worn, but nothing crazy bad. Go to take the coil pack off of plug 2 (i think it's plug 2,center cylinder closest to the fire wall) and its stuck to the plug. Takes a little wiggling and cussing, but finally comes free. The tube is wet and smells of gas. Figure this plug is without a doubt my problem child now. Go to ratchet the plug out and the 5/8s socket ive been using for every other plug wont work. The plug is not seized in there or anything, I can't get the socket to sit down on the hex nut to even begin backing it out. Figure theres some build up down there, take a couple of pictures with my phone to check, not bad but nothing crazy. I spray some brake parts cleaner and later soak some PB blaster down there. Take another couple of pictures and it looks perfectly clean down there no obstructions. Figure this is the end of my problems. Get the socket down there and again still wont seat down on the nut. So I figure the rubber insert is holding me up and grab a regular deep set 5/8s, same issue. Call my buddy over who's built and re-built a few engines, only thing he can make of it is I'm not getting enough clearance on the tube wall. Order a thin-walled 12 point 16mm plug socket off amazon, just got it in tonight. Popped that bad boy down there and still cant even get the damn thing to start catching or seating on the nut. Has anybody come across something like this?

The plug does not appear to be seized, although cant get the socket to grab in order to really know. The nut on the plug has not been rounded or stripped. The nut has not broken loose from the plug, I've tried putting a screwdriver down there to see if I could feel any build up and the nut wont spin freely. And any build up has been chemically removed via a couple different solvents. I'm completely out of ideas on how to get this out and figured I'd plead my case here before taking her into the shop.

So first question, anybody got any ideas on how to get this damn plug out? Secondly, does this sound like it will resolve my weird idle issue or is that another can of worms beyond my problem child plug?

 

Sounds like the plug loosened and the blow by melted the coil. (This is all too common on the J32).

Was the coil totally intact when you pulled it off?

You may have parts of the coil blocking access to the plug nut. You're at a disadvantage with it facing the firewall. Do you have an inspection mirror to get a good look down the tube?
Someone else had a similar situation and was able to use a pair of hemostats to pull out the obstructions:

https://acurazine.com/forums/3g-tl-p...up-big-963519/

 

Looking at the coil and comparing it to another, doesnt seem to be any missing pieces or chunks. Took a number of pictures and videos with my phone. Useful tip, if you turn an Iphone to video you can leave the flash on the whole time, record util you get the shot lined up and then pause and zoom in on the video once you have the angle youre looking for. Really helped me a lot with this so far. But yeah no visible issue from the pictures of the park plug still in the head or when inspecting the coil I pulled off of it. Is it possible for the heat to have warped the nut?

 

That's really strange. Do you have a deep 11/16" or 17mm socket? Maybe try that? Is there any chance that the plug is loose enough for heater hose to unscrew it? (Getting the hose on the plug may be a real trick).

 

16mm thin walled socket wont grab it and 17mm socket is too big to fit down the tube....

Havent tried the heater hose, honestly I'm not sure the plug is that loose.