Where is the 2001 chevy tracker oxygen sensor located?

The 2001 Chevy Tracker's O2 sensors should be found before and after the catalytic converter. The Tracker employS3 sensors total, with sensor 1 installed in the exhaust manifold, number 2 before the cat and number 3 after the converter. They form a valuable link in a vehicle's emission and ignition systems by monitoring the amount of unburnt oxygen exiting the exhaust pipes. This data is sent to the Tracker's main computer and used to inform the engine's air/fuELRatio. When working, an O2 sensor helps to maintain optimal fuel economy and firing. When sensors start to fail or become d***y, readings will be compromised, causing the car to run too "rich" or too "lean" and can result in rough idling, reduced gas mileage and mIS Fires.