Any time? No. Nothing to do with the rear O2 sensor has any effect on engine operation. I even ran a few track days with the CEL on and there was no problem.

Dave

 

What catback are you running?

Which Help Part Number did you buy for the rear o2?

I used 42002 and have not had any problems for a year now.

 

Actually yes it does. If you are running rich, you are running in safe mode and losing a slight amount of power ... Of course there will be no problem the engine is running in safe mode.

 

I don't think there is a limp mode for a secondary o2 code.

 

I used the spark plug anti-fowler trick and it has worked perfect for about 10k miles. I followed how to do it on the one thread on here that everyone seems to follow. I beleive that thread showed using 2 anti-fowlers. When I did this, my sensor rubbed bad, when I only used one, no more rubbing and still no CEL. The car does run really really rich without the cat though. I have to remove the carbon from my bumper every time I wash the car. As for the rear O2 sensor effecting performance....It is my understanding that it is the difference in flow between the first and second sensor that determines if the car is running rich or not (or if there is a cat or not). Similar to how a thermocouple measures the difference in resistance between two dissimilar metals. A thermocouple is calibrated to measure the difference in current between two different types of metal wires and then spit out a reading the same way the ECU measures the difference in flow and spits out a reading. I may be totally wrong, but it makes sense.

 

We're talking about the REAR O2 sensor. It has NOTHING to do with engine operation. If the front one goes then you're stuck in limp mode.

Dave

 

If you pull the plug down that the O2 sensor wires come through I believe there is a connecter where you can disconnect the O2 sensor. You can then remove the hanging wires from the bottom of your car.

-Paul