So I replaced all the spark plugs on bank 2 (easy side) about 20k miles ago and i just never got around to doing the bank 1 side til today.. i know, its better to change them all out together but it slipped my mind til recently
Anyway I removed the 3 coil packs and plugs from bank 1 and to my surprise both the coil packs and plugs had oil residue on it.. not a whole lot but you can see and feel a light coat of oil in some spots
Once i found oil on these plugs i decided to pull all the coils and plugs from bank 2 just to see if these are wet too... luckily bank 2 was dry
I took pictures of all coil packs and the 3 old plugs from bank 1.. I am the 2nd owner of this car and took ownership of it with 87k miles on it, its currently at 148k miles... i am going to assume the plugs were never changed out so keep in mind these plugs probaby have about 148k miles of wear on them.. either way i snapped some pics of the old plugs, how do they look? they have been used for way too long but do they look normal or do they look burnt to you guys?

Now some history with the car.. it was my brother in law's car but gave it to me for a cheap price cause he needed a suv for kids... this car overheated once under his ownership and they had to get it towed.. apparently no work was done on the car after it overheated
after i took ownership of the car it started having random misfires and so i took it to get it inspected and the mechanic said there was coolant in the spark plug chamber plus the car was overheating again and losing coolant... so i brought the car in for a head gasket replacement.. they found that the engine was not damaged but the head gasket warped under all the heat.. so i got the replaced about 3 years ago. Also i just got a compression test done about 5months ago on all 6 cylinders and the report came back that all 6 cylinders had good compression, so the piston/rings are okay

NOW as of today and recently my car feels like its misfiring on cold start ups and the misfires goes away once the car is warmed up.. but im getting really bad mpg (sometimes as low as 19-20mpg and thats with 75% freeway / 25% city driving WHILE driving like a grandma meaning i wont rev past 3500 rpm.. there are times i will get 280 miles on a full tank), stuttering acceleration from a stop (rpm dips a tad below idle and i can feel the car sputter a bit and delay in acceleration from a stop)
No CELs in fact i just passed my Cali Smog test like 3 weeks ago with flying colors but the stuttering acceleration/delay and the horrible mpg is making the driving experience a pain

I guess my next step from here is to replace the valve cover gasket/gommets but can anyone else think of what could be the cause of my symptoms?
Anyone with some knowledge or insight want to chime in on the condition of my old spark plugs? Do they look burnt or is anything out of the ordinary with these old plugs? you can see the oil on the spark plugs, most of the oil i noticed was on the washer
and most of the oil from what i can tell is on the threads/spark side and not the ceramic side


Bank 1 (Firewall Side) Coil Packs




Bank 2 (Closest to Front Bumper) Coil Packs




Comparison of Bank 1 Coil Pack (Right) and Bank 2 Coil Pack (Left)


Bank 1 Spark Plugs (Old)

 

Check you spark plug grommets/rubber seals, it could be misaligned or torn causing oil to seep into the spark plug when they done work in the past & removed the valve cover, I'd replace the rubber seals but your coils look fine to me just clean them up. I had this same issue this year when I did my valve adjustment & found oil in the #4 cylinder spark plug tube. What had come to happen was, when I did my valve adjustment last year (2016), I found the my grommets/rubber seals where not aligned properly.