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Home >> Ford >> 1990 >> Festiva L >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - System/Component Tests >> Engine Sensors & Switches >> Exhaust Gas Oxygen (O2) Sensor
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Exhaust Gas Oxygen (O2) Sensor

  1. Warm engine to operating temperature. Run engine at fast idle. Disconnect O2 sensor. Connect a high impedance voltmeter between O2 sensor and ground.
  2. Observe voltmeter while rapidly accelerating and decelerating engine speed. If voltage is not .5-1.0 volt while accelerating and 0-.4 volt while decelerating, replace O2 sensor. Ensure new O2 sensor has anti-seize compound applied to threads. Tighten sensor to 22-36 ft. lbs. (29-49 N.m).