Check engine light - oxygen sensor gen3

[lout]

fit all your original modules back in as you know that is not the cause
scan bcm with autel to get radio pin number
is this car stock
factory injectors
100% no exhaust leaks

 

[bluehighway]

This is what I hate about supposed modern technology...often it turns into a witch hunt that starts rapidly adding up in expenditure...My understanding is these sensors are to assist either the cat convertor burn or fuel economy/ lean/ richness burn. Theres no mention that the car is not starting or idle adjusting or struggling thru the rev range which it would likely do if the sensors were faulty. When it comes to 'check engine' I traditionally think of oil pressure and temp and maybe alternator warning. Im gonna be naughty and say if it was my car and its driving ok , Id pull the warning bulb and fit an oil pressure gauge and give a right hand middle finger salute to the GM gods... I hope you do find the problem ...modern tech is supposed to help people not send them searching...

 

[lout]

original fault was adding 24% fuel to left bank
this needs to be diagnosed, not ignored

 

[B-Man]

fit all your original modules back in as you know that is not the cause
scan bcm with autel to get radio pin number
is this car stock
factory injectors
100% no exhaust leaks

That's the plan

Where's the radio code located on the autel? I did have a look to see but couldn't see anything under the radio menu.

100% stock
No exhaust leaks that I can tell and mechanic also discounted it.
What's the best way to check an exhaust leak?

 

[B-Man]

This is what I hate about supposed modern technology...often it turns into a witch hunt that starts rapidly adding up in expenditure...My understanding is these sensors are to assist either the cat convertor burn or fuel economy/ lean/ richness burn. Theres no mention that the car is not starting or idle adjusting or struggling thru the rev range which it would likely do if the sensors were faulty. When it comes to 'check engine' I traditionally think of oil pressure and temp and maybe alternator warning. Im gonna be naughty and say if it was my car and its driving ok , Id pull the warning bulb and fit an oil pressure gauge and give a right hand middle finger salute to the GM gods... I hope you do find the problem ...modern tech is supposed to help people not send them searching...

It's been driving "fine" with this issue for about 5 years (doesn't like to idle for too long before it doesn't idle great but doesn't stall and definately running too rich.) Been trying to fix it myself and felt like i would be throwing money into a pit.... then when I got a decent tax check I paid a mechanic and now here we are.
Would have been cheaper to do an o2 delete ‍

 

[lout]

in bcm security, will list radio pin
it would be a noticeable exhaust leak to cause that big of a problem
if you clear fuel trims/disconnect battery does it run better for 5 minutes or worse

 

[B-Man]

Runs the same idles ok to start with then gives a slight cough every so often.
If giving it the beans it still pulls hard.

 

[bluehighway]

Just wondering if it could be a vacuum leak somewhere ?

 

[Drawnnite]

100% stock as in no wiring mods inside either (ie a headunit)?
Only throwing that out there as i chased an O2 problem that was internal wiring (same colours used on multiple circuits, it was connected to the wrong one causing the O2s to play funny)

Another thing I wonder is, point to point resistances of the wiring.
Could there be a high resistance joint or similar causing the O2 to read incorrectly?
If its a millivolt circuit or resistance circuit then this can play havoc.

 

[lout]

what about spark plugs and leads
when were they last changed with quality parts, not ebay