Other than the MPG, will it damage anything if driving with this code???? Upper 02 sensor drivers side- American car. Thanks Ed

 

As it runs rich it'll burn out the cat. (If lean it'll destroy the engine, so it avoids that.)

 

Does anyone have any guess as to how long B4 the cat. goes bad, mileage or time???????

 

Ed, I don't think anyone can give you that answer because a lot depends on driving conditions and what particular backup fueling strategy the car is working in. Change the sensor if that is what the code is for. If you cannot afford to do that, you cannot afford that car!

 

How do you tell which O2 sensor it is?

 

Upper on the left side. P1646 would be the right side.