* Check Engine Light (CEL): This is the most immediate effect. Your engine's computer (PCM) will detect the missing sensors and illuminate the CEL. The truck will likely enter a "limp mode," limiting performance to prevent further damage.
* Rich or Lean Fuel Mixture: The O2 sensors are crucial for feedback to the PCM about the air/fuel ratio in the exhaust. Without them, the PCM will rely on default settings, leading to either a very rich (too much fuel) or lean (too little fuel) mixture.
* Poor Fuel Economy: A consistently rich or lean mixture will drastically reduce your gas mileage. A rich mixture wastes fuel, while a lean mixture can cause engine damage.
* Increased Emissions: An inaccurate air/fuel mixture will result in higher levels of harmful pollutants being emitted from your exhaust. This could lead to failure of emissions testing if required in your area.
* Potential Engine Damage (long-term): Running consistently rich or lean can cause damage to your catalytic converter, spark plugs, and even the engine itself. A lean condition is particularly damaging as it can lead to overheating and melting of engine components.
* Misfires: A lean condition can lead to misfires, causing rough running and potential long-term engine damage.
In short, don't remove your O2 sensors. If you're having issues with them, it's best to diagnose and repair or replace the faulty sensor(s) rather than removing them altogether. A malfunctioning O2 sensor is much better than no O2 sensor at all.
