I know that there is a button to turn on and off O2 sensor. I also see that turning it on seems to initiate some sort of targeting which is why I assume it needs to be off during tuning. However I cant seem to find any technical data pertaining to what it does or how to use it. I'm tuning on turbo 179 ecu. I don't have a stock O2 sensor in the car. Could you fill me in on this feature so I can decide whether or not to install one. Thanks in advance for your help.