The O2 sensors on your 7.3-liter diesel Ford pickup monitor the exhaust gases coming out of your pickup's engine. The O2 sensors are part of the vehicle's emissions control system. When the sensors begin to fail, you will experience a dramatic decrease in your vehicle's engine performance. Your engine will start to burn more fuel to compensate for the damaged or failed sensor, and your "Check Engine" light will come on. You can replace the failed O2 sensors yourself. Replacement O2 sensors can be purchased from most auto parts stores.
Slide underneath your vehicle. Since the 7.3-liter engine is only available on Ford's heavy duty trucks, you should be able to slide under the truck without having to jack up the vehicle. However, if you do need to jack up the vehicle to slide under it, be sure to put the truck on jack stands.
Locate the O2 sensors, toward the front of the vehicle. One sensor will be screwed into the exhaust on the catalytic converter and another will be screwed into the exhaust manifold on the front of the engine.
Unplug the electrical leads from each O2 sensor.
Loosen and remove each sensor by turning the sensor counterclockwise using a socket wrench and the O2 sensor socket.
Thread and tighten the new sensors.
Reconnect the electrical leads to the sensors.
