The answer to 'why is my carbon monoxide detector flickering lights' is that the flickering lights on a carbon monoxide (CO) detector are usually a sign that the device is functioning properly and detecting normal levels of CO in the air. Carbon monoxide detectors are designed to flicker or blink their lights periodically to indicate that they are active and monitoring for CO gas.
The flickering lights are not necessarily a cause for concern, as long as the detector is not sounding any alarms. However, if the lights are flickering erratically or the detector is sounding an alarm, that could indicate a problem that requires further investigation. In that case, it's best to contact a professional electrician or HVAC technician to inspect the detector and the home's ventilation system.