[CCX33911]

I'm not a O2 sensor expert, but my understanding is that they produce accurate results when the materials are at a particular optimal operating range (something like 600 F). The thought with the Cobra is that the O2 sensors are mounted some 30" down stream and may not be operating at the optimal heat range to produce accurate results. The heater would suppliment the heat produced by the exhaust to keep the sensor hot enough. Again I have not measured the temperatures involved nor have I seen specific numbers which would indicate the required operating temperatures, etc.