2003 Silverado

[Joe Batt]

2003 Silverado codes po171. Po174

[Joe Batt]

Just now, Joe Batt said:

2003 Silverado codes po171. Po174

And po161

[Supreme Pizza]

So you have a bad downstream O2 sensor, and system too lean on bank 1 and bank 2 codes.

 

I would replace the sensor ($25), and then clear the codes.

 

If the "po171. Po174" come back, I would check for vacuum leaks using smoke or starting fluid.