* For the 4.3L V6: The upstream O2 sensor(s) are usually located in the exhaust manifold or very close to it. The downstream sensor(s) are typically located in the exhaust pipe after the catalytic converter. You'll likely find them closer to the catalytic converter than the engine itself.
* For the 2.2L I4: This engine also has upstream and downstream O2 sensors. Their location is similar to the V6, in the exhaust manifold (or close to it) for the upstream, and further down the exhaust pipe after the catalytic converter for the downstream.
To find them yourself:
1. Consult a repair manual: A Haynes or Chilton manual specific to your year and engine is your best resource. These manuals have diagrams showing the exact sensor locations.
2. Look under the vehicle: Once you're under the truck, follow the exhaust manifold and exhaust piping. The sensors are usually threaded into the exhaust. They are typically cylindrical with a wire harness connected.
3. Use a diagram from online resources: While a repair manual is best, some online parts stores (like AutoZone or Advance Auto Parts) allow you to select your vehicle and view diagrams. However, be cautious and always double check with a reliable source.
Caution: The exhaust system is hot. Allow the engine to cool completely before attempting to locate the oxygen sensor.
