Fuel Trim Issues - 2015 WRX

I have a 2015 WRX running a Cobb SF intake. I'm running a 93 Stage 1+SF OTS tune.

Recently, I've seen strange fuel trim patterns while I'm driving. Every time I catch it, I try and datalog it. My AF Correction 1 will sometimes have a sawtooth pattern, and sometimes a square wave pattern, flipping between a couple numbers for 5-10 seconds. My DAM value has been fluctuating a bit. It usually sits between .5 and .75. The other day, I saw it hit a new low at .188. Once I get on the interstate, it goes back up. Not quite to 1, but sometimes it'll get back up to .812. It'll go back down in traffic though.

My AF Learning 1 will be around -25ish to -45ish at idle. It'll be above -10 while I'm driving for the most part. Every now and then, it will hesitate and stop responding to acceleration while I'm driving. Sometimes, it will stall out at idle as well. I cleaned the MAF sensor a couple weeks ago and it hasn't hesitated or stalled out as much, but the fuel trims are still odd. The datalogs I attached are from a few days ago.

I bought the car in June of last year. I replaced the spark plugs, rear O2 sensor, fuel pressure regulator, and MAF sensor between July and August. The issue didn't happen much over the winter, but returned around March. I live in Kentucky in the U.S., so I wasn't sure if the air temp and humidity would be huge factors. The past couple months, I've replaced the turbo (separate issue: oil seals went bad) with a remanufactured OE turbo, and replaced the front O2 sensor and all four fuel injectors.

I'm not sure if anything mechanical would cause the issues I'm having. I'm wanting to guess it's the compensation tables, but I'm not 100%. I can't use Accesstuner, so I'm just datalogging as much as possible and trying to gain some info and guidance before I switch to Ecuflash and have to do the MAF scaling and everything. Asking for any suggestions on what could be the cause, or any different parameters I need to log.

Personally, i would be looking pretty hard at the upstream O2 sensor. I had a van that would run really poorly until I started driving, like you describe. How many miles are on it? It may be due for a quality replacement

Otherwise, i had another van (i like vans) that had a super corroded chassis ground, causing the fuel pump to fail intermittently. It took a while to catch. All this to say, it could be wiring, affected by weather conditions. But i feel like your Subaru is a bit too new to be having those issues.

I cant open the pictures for some reason either, sorry. Id be curious what the MAP values are when this happens as well

I just replaced the upstream O2 sensor a few weeks ago. The voltage looked normal on the new one, so I haven't logged the voltage for it in a bit.

From this recent datalog, the MAP read between 8-10 psi for the square wave pattern and from 13 down to 7 back to 11 psi for the sawtooth pattern. The square wave pattern went on for about 7 seconds and the sawtooth pattern went on for about 15 seconds. I didn't realize only gold members could open images, so I'm not sure the best way to describe it.

The carfax report said that my car did come from the north, so I may need to check for corroded grounds. Thank you for the suggestion.

I also noticed most of the time, it does the odd fuel trims in 5th gear, but not always.

I just looked at the log, it looks like your TPS signal is dropping out, that could be part of it too. Although I would expect a code if that were the case.

What brand of o2 sensor did you go with? I have had issues with some of the more dubious sensors. Sometimes they can die pretty fast

I'll see if I can log the TPS voltage and find anything abnormal.

I went with a denso O2 sensor.