Oxygen Sensor Question

[JP4RNR]

Even if you do not have any malfunction codes is it still possible to have a faulty 02 sensor that even the ECU cannot detect?

 

[toto]

My understanding is that yes, O2 sensors lose their effectiveness over time. While the computer doesn't think the sensor is broken, a failing O2 sensor can have a negative effect on gas mileage. I've read about people changing them proactively as early as 75,000 miles for this reason.

 

[a77boy]

dam,, maybe thats why my V8 4wd has shi**y gas mileage. Or maybe its just my lead foot

 

[toto]

My V8 only has 7,000 miles, so in my case I know it's the lead foot!