* Reduced engine power: The exhaust system will be significantly restricted, leading to a loss of power and performance.
* Poor fuel economy: The engine will work harder to expel exhaust gases, leading to lower fuel mileage.
* Rough running: The engine may run rough, misfire, or stall, especially at lower RPMs.
* Check engine light: The car's onboard diagnostic system (OBD-II) will almost certainly detect a problem and illuminate the check engine light. This will store a diagnostic trouble code (DTC) related to the catalytic converter.
* Harmful emissions: The most significant consequence is the release of significantly higher levels of pollutants into the atmosphere. This is illegal in most jurisdictions.
In short, removing the catalytic converter is detrimental to the vehicle's performance and is environmentally irresponsible. It's best to repair or replace a malfunctioning catalytic converter rather than remove it.
