Service engine soon

[02_Tahoe]

that was the code I got on mine, was intermittent at first, then it stayed on. then the car started running BAD, and using a lot of gas.

replace your O2 sensor. Dont even mess with anything else.

So the sensor is bad or do I have an exhaust leak. Finding the code just created more questions

 

[Justin]

Rear O2 sensors do not have any impact on engine operation, they serve to monitor the efficiency of the catalytic converter only. No need to rush out and change it.

Knock sensor codes on the other hand will result in up to 10 degrees of ignition timing retard from target. Those codes will result in a 30-40hp loss or more.

 

[02_Tahoe]

Rear O2 sensors do not have any impact on engine operation, they serve to monitor the efficiency of the catalytic converter only. No need to rush out and change it.

Knock sensor codes on the other hand will result in up to 10 degrees of ignition timing retard from target. Those codes will result in a 30-40hp loss or more.

Thank you, now I can relax. And I sent an email to you asking the same thing so you can just ignore that. Thanks for the help

 

[jarydM]

So the sensor is bad or do I have an exhaust leak. Finding the code just created more questions

I'm sorry, I did not read this as Downstream O2.

if it coded, it probably *IS* bad, but it won't affect the engine. Its just telling you it can no longer monitor your post Cat emissions.

 

[jarydM]

I'm sorry, I did not read this as Downstream O2.

if it coded, it probably *IS* bad, but it won't affect the engine. Its just telling you it can no longer monitor your post Cat emissions.

nm, @Justin beat me to it.

 

[02_Tahoe]

nm, @Justin beat me to it.

I guess yours was before the cat? I've read a bunch of threads where an o2 sensor was bad before the cat and it caused rough idles, stalling, loss of power and many other problems.

 

[jarydM]

I guess yours was before the cat? I've read a bunch of threads where an o2 sensor was bad before the cat and it caused rough idles, stalling, loss of power and many other problems.

yeah, up steam O2

at first it wasn't anything, within a week I thought she was going terminal. Replaced it, and it runs just like new again.

 

[iamdub]

Yes- rear O2 is there only to monitor the catalytic converter's efficiency. I think Maryland is strict and probably looks into it, but if it's possible in your state, I'd have Justin tune out the rear O2 sensors and have the cat deleted or get a "fake cat" in it's place if that'll get you through inspections.

 

[02_Tahoe]

Yes- rear O2 is there only to monitor the catalytic converter's efficiency. I think Maryland is strict and probably looks into it, but if it's possible in your state, I'd have Justin tune out the rear O2 sensors and have the cat deleted or get a "fake cat" in it's place if that'll get you through inspections.

Yeah Maryland emissions is very strict, lucky me....no catless y-pipe with long tubes for me. And I can have Justin tune it out, I have another year before I need to test emissions again