[AntonLargiader]

That's getting kind of interesting. At the times that the idle goes up, the BMS is decreasing the injection times and raising the stepper value (I don't know if that means more air or less air). However, both of those are outputs. I think we need to look at inputs to figure out what the BMS is responding to. I can't tell if the BMS is responding to the increase in idle speed or if it's causing it in response to something else, but it sort of looks like it's responding to it.

Inputs would be air temp, engine temp, O2, RPM, knock. Do you have temperature logs?

The O2 sensor voltage drops down very low during that time, which is lean. Is it possible that you have an air leak? I wish I knew which way the stepper worked. If the BMS is decreasing the fuel and air, then it's probably responding to an outside influence.

Have you checked the fuel pressure?

BTW I also don't understand those throttle position values, but it seemto be going between zero and full. Could it be as simple as a bad TPS? Or bad wiring to the TPS, or a problem within the BMS?