oxygen sensor question

[dwmmatt23]

lately my exhaust system has been starting do develop a rattle/vibration. only seems to be when in gear with foot on the brake. got under it today and it sounds like it is comming from the passenger side o2 sensor after the cat. i have also been getiing a CEL with code p0420, low catalyst so thought it might be the sensor. but i think that code is for the drivers side? my question is if a sensor goes out can the tip of the sensor inside the exhaust be loose and rattling?

 

[Rivieraracing]

Have you tried hitting on the catalytic converter and see if you hear the media bouncing around?

 

[dwmmatt23]

ill check again, i shook it around and didnt sound like it was the cat. but the sound its making when im sitting in the car sounds way louder than a small o2 sensor could make.

 

[jhellwig]

Could be a heat shield rattling.

 

[yooformula]

I have the same code being set the last day or so on mine with high miles(180k miles) and a few local gm techs gave me this info..

"When the P0420 code sets it is only because the 4 O2 sensors are functioning properly and they have determined that the converter is not performing optimally, and needs to be replaced.....OHH, and not to pee in your oatmeal, both of the converters are in the
Y-pipe, you get to replace them both. "

"The catalyst efficiency test are done with O2's.
They only test oxygen content in exhaust.
The cat's are going when they loose the ability to use & store O2.

That milage those converters are likely done. Both sides.
If it set a 420 bank 1, a P0430 is prolly not far off."