IAC maybe?

[wrangler94]

Originally Posted by ChevyTech

Glad you are making progress.

I would not replace any sensor just to replace parts as you have funds to do so.

The quality of replacement parts is poor. I would prefer a used good original parts over much of what is being produced today.

When you buy a new oxygen sensor I suggest staying away from BOSCH brand.

Just adding another update. Truck has not shut off at random now for 2, maybe 3 weeks now. Thank you again for all the help with that.
I did replace the O2 sensor saturday and it stays in closed loop as it should now, mostly at least. Not sure how much it should cycle to open, but it's almost always closed now.
When replacing the fuel filter i found hacked together wiring for the transmission plug for the 4L80E and wasn't sure what to think, until I did some digging and the plug has been updated, but it looks like a monkey with a butterknife did the upgrade. At this point I'm happy and not gonna chase it so hard, but the scanner does show that the torque convertor never locks up.
Obviously the bad wiring job is a prime suspect, but research has shown that a bad brake light switch can cause it too, and when the scan tool is plugged in i throw a code (not on scanner, in flashing brake light warning) of stop light switch. Scanner shows that brakes are off or on as i press the pedal, and brake lights work, but is it possible that the switch is somehow not giving the transmission what it needs? The computer seems to get signal, but that code does keep coming up, even with resetting the computer. Again, only when the scan tool is hooked up. I unplug scaner and brake warning light goes off again.