PULLING MY HAIR OVER A P0301 code!!

[CrashTestDummy]

Finish replacing the plugs, AND, I'd recommend, a fresh set of plug wires. Our '12 Caprice developed a miss, and after swapping things around and not getting resolution, I threw a fresh set of AC plugs and Delco wires on it. All the codes cleared. This is the first 'modern' car we've owned where plugs/wires would cause a miss, and a fresh set of both actually fixed the issue.

All of the plugs came out looking used, but clean and with good color. The plugs you show in the attachments above look like cr@p!

 

[RET423]

My 2 cents
Your misfire turns off the stabilitrack when it occurs

Your misfire wasn't properly diagnosed

Always move a coil pack to see if the miss moves with the coil pack, if it doesn't leave the coil packs alone

Do the same with the spark plug and wire unless there is something obviously bad, see if the miss moves

If the miss moves you have found the problem & know what to buy, if the miss didn't move, move the injector next & see if the miss moves

If not your problem is in the cylinder and you haven't spent any money yet

Now you check compression but with the white smoke I think your going to have a blown head gasket

 

[dkad260]

That spark plug is terrible looking, no chance on earth it's going to fire. I would definitely perform a compression test on at least Cyl 1&3, then 2&4....and compare.

Do you have a restricted PCV system, maybe a catch can that's clogged?

I agree the white smoke is not a good sign. What does the dipstick look like? Hopefully just oil and not a milkshake.