Logs - MAF Reading Suspicious?

I am still learning this stuff but I'm either getting better or luckier. Either is actually fine.

Strictly ghettos tools here. A bluetooth OBDII adaptor, Torque Pro software, and an Android phone. (I have better stuff but this is easy and it's cold.)

Does a small change in throttle and a large change in MAF grams/sec indicate a wonky sensor?

OBDII Partial Log

Nah, I'm OK with those readings. From what I can tell, the MAF reading only increased about 13 g/s, which isn't all that much when cruising down the highway. The trims stayed happy, the A/F didn't show a big shift in ratio, and the MAP showed a corresponding change in intake pressure.

Your MAF may actually be wonky? :silly: It just wasn't wonky during this capture.

Thanks. I have a new MAF on the way. I have a couple of cars that use the same MAF and I figure I'll need one sooner or later.

I am chasing a Cat below efficiency threshold (P0420) on a Subaru. It was happening every day but only once since I started logging. It has maybe 2 years on the A/F sensor and downstream O2 and around a year on the cat. It was really cold when it was happening every day so it's hard not to suspect that temperature is a factor. Now that I'm logging data, no code. Today I'm going to use my good scanner to verify that we haven't somehow ruined the new cat, then do a smoke test on the vacuum hoses and the exhaust. I really want to be the guy to solve this one but I don't expect it to be easy. The more I read, the more things I see that can be the issue. Apparently the front bumper, the rear tail lights, and everything in between can cause it to randomly throw the code (just kidding).

This is my son's car and I am trying to teach him that we don't drive around with check engine light on. We fix the underlying problem. Easier said than done in this case...