I have a Manual 97 Mazda Lantis 323 1.8L DOHC 16 Valve BP and was wondering if the EMU / ECU on it learns? Could unplugging the battery to reset it help some of my problems with erratic idle? I found a wire disconnected which when connected prevented the car from starting. Maybe the EMU just needs to be reset after connecting the wire?
Yes, most car ECU's learn. I'm going to assume yours is no different. If you decide to replace the coolant temperature sensor, I'd disconnect the battery at that time. When you get everything back together, it should have it's volatile memory erased and your car can start from jump street. Some cars ECU's erase in a matter of a couple of minutes, others can take 20-30 minutes. I'd go for the latter and call it a day.
This was a good thought on your part and I would definitely do this.