Been to long since I done mine but you got 3 wires 1 goes to the 02sensor other 1 goes to ignition and the other 1 goes to a good earth. Just double check with that
When boosting it more then 4000rpm my car back fires and power cuts in and out. when I look at the air/fuel gauge when putting my foot down it goes straight to lean. Recently had car tuned but since have changed dump pipe could this be the problem??