Random errors would point to an ECU error or ground/power error
you show variances in voltage, but without a baseline from a good car I don't know if those are normal or not
a brief unrelated example:
My 70 +2 ran and drove fine. Then one day, it did not want to crank. Finally did but did not charge.
Checked all my connections, including the battery ground, which bolts through a bobbin in the body and into the chassis, all are tight.
This behavior continued for several weeks.
One day driving down my very slow, very curvy street, I noticed a pattern to the amp gauge. Turn one way and it charged, the other way it did not.
I returned to the garage and laying on my back turned the bolt head for the battery ground/chassis body bolt.
It turned easily
when checked from above it was tight,but that just meant the battery cable was tight to the body, not the chassis, the bolt had slowly wound down, the threads on the nut and threaded bobbin remained tight to each other but not to the chassis. when cornering it finally got loose enough that the body lifted off of the chassis, making the problem obvious.
the point of my story is that problems are rarely complex, but that does not make them easy to find
Imagine if that car had a computer.............