2005 Chevy Monte Carlo 3.4l V6.
Check engine light. Scanned code P0172 - rich. Replaced first o2 sensor. What else can the problem be if the o2 sensor graph is still dropping and raising then staying low .
Answer: A rich code, but with an oxygen sensor showing lean is odd.
I would suspect that this is not an oxygen sensor problem, but possibly a programming issue with the PCM
There sis a bulletin for a false rich code. Re-flash of the computer would be needed. The dealer would need to do that. A check of your VIN is the only way to see if your vehicle is involved in this bulletin. This is not a recall, just a service bulletin, also known as a TSB.
Silverado IAT Sensor Wire Colors
What are the color of the wires for IAT sensor on the MAF plug 2000 Chevrolet Silverado 6.0L Vortec V8.
Answer: The black wire is the sensor ground. The ground is internal to the PCM.
The TAN (terminal B)wire is the 5 volt reference / sensor signal wire. Also from the PCM.