* Poor Fuel Economy: The oxygen sensor is crucial for the engine's computer (PCM) to determine the correct air/fuel mixture. Without it, the engine will run in a "default" or "open-loop" mode, using a pre-programmed fuel mixture. This will be significantly less efficient, leading to much lower gas mileage.
* Increased Emissions: The engine will run richer (more fuel) than necessary, resulting in significantly higher emissions of pollutants. This can lead to failing emissions tests in areas where they are required.
* Check Engine Light: The check engine light will almost certainly be illuminated. This light indicates a problem that needs attention. Ignoring it could lead to further, potentially more expensive issues down the line.
* Catalyst Damage: Running rich for extended periods can damage the catalytic converter, a very expensive component to replace.
* Potential Engine Damage: While not immediate, consistently running rich can lead to fouled spark plugs, excessive carbon buildup, and other engine problems in the long run.
In short, while you *can* run the truck without the oxygen sensor, it's a bad idea. The benefits are minimal to none, while the drawbacks are substantial. Replacing the oxygen sensor is a relatively inexpensive repair that will restore proper engine function and fuel efficiency.
