The Chevy Blazer has the same 4.3 liter engine, the same chassis and the same exhaust components from 1994 to 1999. This includes the two oxygen sensors. The bank one sensor is located on the left side (drivers side) of the front exhaust Y-pipe. The bank two sensor is located just before the catalytic convertor in the exhaust pipe. Which oxygen sensor needs to be replaced will require an OBD II (
