In some calibrations you can select OL or CL at idle. Originally GM had CL to help pass emissions. Depending on where your O2 Sensor is located, a one wire may get too cold so, it'll drop out of CL. With a heated one you'll go into and stay in CL as soon as your water temp reaches a certain point (in the .bin).
I see the
@grampadirt log is spaced in ~90 second increments while the
@termite one is ~10 seconds so, grampa's looks even more erratic than if it was in 10 seconds.
I went back to when I was using TunerPro RT to tune my 7747 on 02-04-19. Of course the old ECM only updates ~every second (160 baud) where the 7427 is 8192 or ~50 times faster but, you'll kinda get the idea.
In the second graph, you'll see the heated O2 crossing (Cross Counts) over and under 450 mV, which is supposed to be ~14.7 AFR .
In the bottom graph, you'll see that MAP pretty well follows TPS and then RPM does too. Please disregard the spike at between 4:00 and 4:10, that's when I caught my ICM wigging out, LOL.
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I agree with grampa - something is probably going on with your O2