I think my XJ is possessed! Most times when I try to start the engine, it doesn't turn over the first couple of times, I just hear a hum, then it will crank and run normally MOST times, however that is the other thing that's going on - yesterday when it started the rpms would bounce up and down, mostly at idle.and my REM engone monitor showed readings all over the place (voltage ranging from 9-22 volts (gauge in dash showed approx. 13 volts), MAP reading from 7-15, coolant temp was registering 0 degrees (gauge in dash was registering normal op temp)

I had thought maybe AIdle Air Control valve, but that would only explain the up & down rpms at idle and the engine shutting off while idling.
ECU maybe? Could an electrical issue in the IAC cause any of these other issues?

I was unable to upload two 20 second videos, but here is a link to them that can be copied and pasted into browser :

https://photos.app.goo.gl/54hCcvU2HdAmJEJF8