My 05 cobalt ss/sc keeps resetting the codes for O2 sensor... As far as performance, driving in town at lower speeds it seems to choke some, but if you "get in it" it runs good. P0133 - B1S1, P0172 - Fuel system rich, P1133 - Insufficent switching. I have replaced the O2 sensor with OEM three times and replaced the pigtail with OEM. Any ideas why or what could be causing this? In desperate need of advise!!!

 

When u say oem u talking from the dealership or other

 

Just because the O2 sensor isn't switching properly doesn't mean the sensor is bad. You could very well be running really rich. Is this car tuned? When was the last time the injectors were cleaned? How is the air filter? Could your laminova cores be clogged? My laminovas in the SC kit I bought were clogged as ****.

 

yes I have replaced with ACDelco part.

I have not checked the laminova cores, was hoping there might be something a little less involved.. The injectors are new and the air filter is clean... it is definitly running rich, thats why I replaced the injectors thinking I had one leaking. It has not been tuned.

 

Is the car stock?

 

The only mods it has is injen cold air intake, pace setter headers, and no cat. I have gotten conflicting stories as far as the cat... some people say that no cat will not have an affect on the front O2 sensor and other people say that there is not enough back pressure for the front O2 sensor... So I am not sure.

 

well if it was a back pressure issue all the guys successfully running catless should have problems.... (hint hint they dont)

honestly seems like you have a bad o2 sensor in bank 1 and the second is just because the cat isn't that good at being a cat

 

Do you have a catless downpipe? If so does it have a slanted o2 bung? If not it will read very rich on the O2 sensor and possibly foul up the sensor. You may need to replace the sensor or at very least clean it.

 

Ok.... There is no cat anywhere in the exhaust. The O2 is straight in the pipe. I just replaced it again with another ACDelco OEM part. When the O2 is not reading it runs very rich but for the two days that the new O2 worked properly, it ran like a champ! But after it stopped working again, you can smell fuel in the exhaust and runs like it is flooded until you get to about 3000rpm's, then takes off beautifully. I am confused why this O2 sensor seems to continuously go out...

 

LSJ's have a narrow band o2 sensor, not a wideband sensor. So the o2 sensor can only register within a certain value of AFR and make adjustments to the fuel injection mass.

Have you owned the car the entire life of it? Or did you pick it up used and then install the injen intake? I'm leaning towards it was tuned with a bad injector so now with an injector firing correctly its stupid rich in the VE tables

 

I did buy it used and everything that it has been done to it was done before I bought it. I am by no means a mechanic and I don't race... so I am just trying to understand what I might need to have done to it. Thanks for all suggestions!

 

Do you have any way to watch what the car is doing?

Can you read the fuel trims to see how far off it is.

 

No...

 

If you can find someone with HPtuners they can log things for you and potentially give you a revised tune file to correct the VE tables (which I'm assuming are the ones that are off since after 3000rpm it starts running smoother)