1997 Chevy Surburbon oxygen sensors

Is there a way to verify that my oxygen sensors are causing me to run rich in both banks?

If the Check Engine light is on, all that needs to done is to connect a scanner to verify if there any O2 sensor codes. If there are, then the scanner would be used to look at the crosscounts of the O2 sensors to see if they’re operating correctly.

If the Check Engine light isn’t on, there’s nothing wrong with the O2 sensors.

Tester

What are the symptoms and why do you suspect O2 sensors?