[V8] New O2 Sensor- Whhhhaaaatt

[rudedog714]

Here's a head scratcher, at least for me. I just replaced my O2 sensor, went with the 4 lead type. Now the thing is fine until it warms up the it seems to run too rich. Flat stretch of road at a steady 65 MPH should give me 25-28 MPG instead it's 15-17 MPG then it'll go back to normal for a bit and back to running too rich. I've double checked all the connections and the extra ground lead is on a bolt behind the drivers side head. What's going on here, I'm baffled. Thanks in advance for all the incredible Audi expertise, William