Ok, update:

It was suggested to me to check the throttle body. Maybe there is a flat spot or something, and when it warms up it will not engage fully or gets stuck.
So with my new sensor and app I monitored the throttle position, or rather tried to. There was too much delay so that didn't really work, but...

Now there is a new code.
P0107, Manifold Absolute Preasure/Barometric Pressure Circuit Low Input.

After researching what the MAP sensor does, and the difference between the Map sensor & the MAF sensor (I don't have one) I decided to try swapping it out with a new sensor, and worse case scenario I'll just take it back if it doesn't work.

Cleared the codes, drove it enough to warm it up, turned it off & on again...
Seems to be driving fine. Actually a little better than before!


I'll wait to see what codes come back up, and certainly report back if the problem returns, but if I don't then it was the MAP sensor.