Where is the 02 sensor on a Chevy G-20 with 350 V8?

The location of the O2 sensor on a Chevy G20 with a 350 V8 depends on the year of the vehicle. There's no single answer. These trucks often had one or more O2 sensors in different locations depending on the emissions system and year of manufacture.

To find it, you'll need to:

1. Consult your vehicle's repair manual: This is the most reliable way to find the exact location of your O2 sensor(s). The manual will have diagrams showing the sensor placement.

2. Check online resources: Websites like AutoZone, Advance Auto Parts, or similar parts retailers often have diagrams showing sensor locations based on year and engine. You'll need to enter your vehicle's year, make, model, and engine size.

3. Look near the exhaust manifold or catalytic converter: O2 sensors are typically located in the exhaust system's pipes, often near the manifold or just before or after the catalytic converter. They're usually threaded into a bung in the exhaust pipe. Look for a wire harness connected to a sensor in that area. Be cautious, the exhaust system is hot!

4. Visually inspect the exhaust system: Carefully trace the exhaust pipes from the engine back. The sensor is usually in a relatively accessible spot for replacement.

Without the year of your G20, providing a specific location is impossible. Remember to always consult your repair manual or reliable online resources for your specific vehicle year and model.