signinffs

Hello. This is a long read, but Im trying to give history as best as I can to aid in diagnostics. If you want a real puzzle with what I dont see as any obvious solutions, here it is.
I've been having a variety of issues that all seem to be connected but I can't figure out why. I have already covered a lot of the basics that I will write down below. This has been an ongoing problem for 6 months and got really bad the past month to the point where I dont want to drive it anywhere past a few miles from my house, so buckle up

Car specs:
2010 IS250 AWD Automatic
167,000miles
Got the car with 130k on it and maintained it myself ever since. It is not rusty, has never leaked any fluid, and lived most of it's life in Tennessee and everything works just fine. I do a variety of city/highway driving.
Since I know the car is old, I dont ever mash on the gas until the car gets to operating temps. I keep it under 2k rpms at all times until its fully warmed up.
Oil change every 5k miles. Currently have not done one in 3.5k miles.

Issue:
About 6 months ago (3-4k miles ago) I was driving for a while (car at operating temp) and stopped at a red light with the car at idle, and then it just died (plenty of gas left). No check engine, no lights, just engine turned off, accessories remained on. I switched it to park, turned it on again, and it was like brand new. No weird noises, behaved as usual, no codes, everything was perfectly fine. I thought that was weird but I figured if there was an issue it would present itself, so I continued to drive it regularly and nothing like that happened again until about 3 months ago when once again the same thing happened. And again, as soon as I turned it back on, no issues.

Then about 2 months ago, it became more regular, like it would happen about once a week, so I started looking into it. Eventually the issue got worse, it started bogging down where the rpms would drop about 2-300, at idle and then come back. Usually it would recover, sometimes it would die. Eventually it threw a code, P0103, MAF sensor circuit high.
I investigated, checked MAF sensor, looked perfectly fine. Cleaned it with MAF sensor cleaner. Drove around, no change.
Replaced MAF sensor, drove around, no change. So I returned the new one and put my old one back in. (currently has old one)
Replaced all spark plugs. (DENSO Iridium FK20HBR11). No change.

Now the issue again got worse. On top of it dying at idle, about a month ago while driving, I went to accelerate rapidly on the highway and it "slipped" and threw up a check engine light and traction control light It's like the car had no power. I was going around 40mph, and it felt like the car was just in neutral. I can rev it all the way up to 4.5k, and it would barely have any power while in drive. I stopped on the side of the highway. It shifted into reverse, and I could drive backwards, and in forward it barely had any power, but it could drive. I restarted the car, and it was like new again. It had power again, I was able to accelerate, and I came back home. Checked the codes, still the P0103. I cleared it previously, but it had come back, at this point it is labeled as "permanent" with my scan tool. Also most recently got a P0300 code for random misfires on random cylinders, which leads me to believe its not a coil and if it is, so help me god.

Now, any time I drive it, it loses power to the wheels whenever I accelerate quickly, after which I would stop, restart the car, and then it would be okay, and now even that wont fix it sometimes. It's a crapshoot.
I tried a bunch of stuff to remedy the situation with no luck in pinpointing the issue:
-Vacuum tested it with homemade smoke machine (look up smoke machine under $10 on youtube)
-Changed spark plugs
-Compression tested all cylinders, all are good, in order of cylinder they are: 130 133 125 125 125 127
-PCV valve I checked by taking it off while car was running and putting my finger over it, vacuum was there and the blockage did lower my RPM by about 100, but the car was able to recover and not die.
-Added seafoam to a quarter tank of gas to see if that would clear out some injector blockage, but I suspect this is an air issue.
-I just replaced my transmission oil with Toyota ATF WS along with Geniune toyota filter and tranny gasket, crush washers, o ring, the whole 9 yards, suspecting that it may somehow have been a tranny issue. Fluid did not have any shiny metal bits, idk when the fluid was last replaced so I did it to make sure. It was black, but not sludgy or anything. (idc if toyota says fluid is lifetime, that's not how fluids work). No dice.
-Tried to reset ECU by leaving batter disconnected for an hour. No change.
-Replaced throttle body thinking that a certain range in the variable resistor within the throttle body was worn out due to age. Didn't want to back probe original to see in case I screwed something up. Got an aftermarket throttle body from JDM Speed, it was pretty cheap on ebay. Currently have the aftermarket one in the car, but it didnt help.

Things I have NOT tried:
-Vacuum testing the system, still getting around to it.
-Replacing ignition coil because I got a P0300 code where all cylinders were misfiring so I doubt it was multiple coils going bad simultaneously. All coils are Toyota DENSO 90919-02256 and look original.
-Adding seafoam to intake for deep cleaning, still getting around to it.


Also, I have done a carbon buildup cleaning of my valve stems about a year ago. During that time I replaced spark plugs, new intake manifold gaskets, even cleaned injectors using homemade injector cleaning tool by blasting a bunch of carb cleaner through them using a switch, and PCV valve. It worked like a charm and I went from 16mpg to 25. Currently I am at 18mpg likely as a result of this issue.

While checking the PCV valve just now, I did notice the part number was wrong (it was for the IS350 PN 1220431050). This was my fault from when I replaced it last year during the carbon buildup cleaning. I ordered the correct PCV valve and the little hose that goes from it to the intake manifold (PN 1226131060) cause I saw it was a little dry rotted, but smoke test did not show it having holes. Replacing just in case.
I suspect there is something bigger at play here though, I don't think PCV alone would cause this many issues but we'll see.

Currently car runs like **** at idle, fluctuates constantly from 730-800 rpm constantly at operating temps, it wont settle. I did a drive after the tranny oil change and it ran SUPER rough. I found that one of the spark plugs I recently changed (under 300 miles on it) had a broken off spark electrode on cylinder 2. It kind of just reseeded back into the spark plug? You can hear it shake inside. I replaced it but not sure what could have broken it. I didnt over torque the sparks when I changed them 300 miles ago. The rest of the spark plugs had some oil on the threads but the tips looked good. Not burned, not ashy, just the right amount.


Ill keep editing this list as I go with things I tried, but please feel free to suggest anything else you think it may be. I am at a loss here.

signinffs

Update:
Car was running rough cause another spark plug was missing an electrode, this time on cylinder #1, last time it was on cylinder #2. I will change it tomorrow when the parts store opened. This makes me think that when I bought all 6 sparks on ebay a while ago, they were likely fake and garbage quality, despite it saying made in japan and all the right markings on all of them. All together they were like 30 something dollars, but this one single spark that I replaced today was 20 something dollars. Will update tomorrow.

2013FSport

iTrader: (2)

Where did you buy those plugs? There are counterfit look alikes out there. I see you have a code reader but I myself would use a phone app and do some data logging of vital signs. In this way when it is running okay you can compare it to when it misbehaved and hopefully pin point the issue.

As for those PSI readings, what was the method, was the battery fully charged, do you have an air compressor to tee into that gauge and test it for accuracy? 130 psi is very low. A low battery, high altitude and not opening the intake to air can cause some of this but not that much as you should be seeing north of 180 psi. IIRC 195 is nominal.

After it misbehaves, does it show any pending codes?

I'd start logging data before throwing new parts at it.
RPM, MAF, TP, IGN ADVANCE, SPEED, Calculated Engine Load.
​​Others to switch in and out:
​STFT's, LTFT's
Knock sensor data
B1/B2 O2 sensor data for AFR

At a glance, two broken plugs, please compare these to those you pulled out. Font, welds, shape of everything, embossed font on steel body. That ain't right unless dropped and abused before they landed in your hands.