Persistent CEL for cylinder misfire

So here's the backstory. 2004 Prerunner, 4 cyl, 2.7L, 2WD, 220k miles. A bit over a year ago I started getting a real bad misfire. The whole truck would jerk hard, over and over, the whole time it was running, so I assume one cylinder was fully dead. CEL obviously, and every once in a while it would even blink, which I read is because fuel is passing into the exhaust and damaging the cat. Took a while to fix the situation cause I have 3 kids and just can't ever get the time to work on stuff like this. I work remote now so I don't have to drive it all that often, but I admit there were a few times that I had to get somewhere and so I did drive it around town like this a few times when it just needed to be done.

Got the code read at Autozone (didn't have my own reader then, but do now) and they said misfire in cylinder 2. Eventually ordered new OEM plugs and coils for all 4 cylinders since it had been a while and changed them all out hoping that would do it. When I got in there I found that the plug in cyl 2 was completely loose, which I've now read isn't all that uncommon, and there was a bunch of residue in the well and on the coil from the blow by.

Good news was it seemed to solve the problem, no more serious misfire, and the truck feels better, but bad news was that ever since then I still get the code for cyl 2 misfire popping up over and over. I read it, clear it, and a few days later it comes back again, even though I'm not feeling shaking or anything. Sometimes I feel like there might be a little imbalance in the idle or on accel from idle, but I could just be convincing myself too. Sometimes the CEL will blink for a couple seconds and then still turn back off on its own.

It was March 2022 that I swapped all the plugs and coils and Ive been dealing with the persistent CEL ever since. A couple weeks ago I got back in there and swapped the plugs and boots from cyl's 1 and 2. Code still comes up as cyl 2.

Any ideas what else might be causing the misfire code when it doesn't feel like it's misfiring? I've seen other posts with similar issues talk about cleaning the throttle body and the MAF sensor. Should those be my next shot?

Here's the real kicker. Registration is already a few months expired cause I need a smog check this time and I'm 99% sure I can't pass smog with this CEL issue. Gotta get this fixed before I get impounded

Any advice would be greatly appreciated!

 

Do a compression test and measure your valve shim clearances. Some could be worn which can affect compression and contribute to intermittent misfire. Make any adjustments needed and do another compression test to see if anything changed.