Oxygen (O2) Sensor

O2 sensor is located at outlet of exhaust manifold. Warm engine until coolant temperature reaches 185-205°F (85-95°C). Disconnect oxygen sensor connector, and connect a voltmeter to connector. With engine speed more than 1300 RPM, measure oxygen sensor output voltage. Voltage should be .6-1.0 volt. If voltage is not within specification, replace oxygen sensor.