Where is the oxygen sensor on a Chevy G 20?

The location of the oxygen sensor(s) on a Chevy G20 van depends heavily on the year and engine. G20s spanned many years and used various engines (including V6 and V8s). There's likely to be at least one upstream sensor (before the catalytic converter) and potentially one or more downstream sensors (after the catalytic converter).

To find the sensor(s) on *your* specific Chevy G20, you'll need to:

1. Find your vehicle's year and engine type: This information is usually found on your vehicle's identification plate (often located on the driver's side dashboard or door jamb).

2. Consult a repair manual: A repair manual specific to your year and model G20 will have diagrams showing the exact location of the oxygen sensors. You can find these manuals online (often in PDF format) or at auto parts stores.

3. Use an online parts diagram: Many auto parts websites (like AutoZone, Advance Auto Parts, etc.) allow you to select your vehicle's year, make, model, and engine, and then view diagrams showing the location of various components, including oxygen sensors.

Without knowing the specific year and engine of your G20, it's impossible to give a precise location. Generally, they are located in the exhaust manifold or the exhaust pipe close to the manifold for the upstream sensor(s), and further down the exhaust system for the downstream sensor(s). They are usually threaded into the exhaust system.