Originally Posted by Tony1616

I use a new oscilloscope for the test, and a new o2 sensor form ebay ( https://www.ebay.it/itm/361467036850) at idle i have the wawe form like your image, the voltage change from 0.1 to 0.75 3 times a second.
But if i try turn a little knob holding the throttle steady the trace became flat and at 0v.