Unclogging a catalytic converter without removing it is a challenging task, and it’s important to note that attempting to unclog it may not always be successful. If your catalytic converter is severely clogged, damaged, or malfunctioning, it is generally recommended to replace it for optimal performance. However, if you still want to attempt to unclog it, here are a few methods: Catalytic Converter Cleaner. These products are designed to break down carbon deposits and other contaminants that may be causing a partial blockage. Follow the instructions on the cleaner product carefully. Highway Driving. Take your vehicle for an extended drive on the highway. Frequent acceleration and deceleration during highway driving may create a pulsating airflow that could help dislodge some deposits. Professional Cleaning Services. Some auto garages offer professional cleaning services for catalytic converters. They use specialized equipment to flush out deposits. However, this method may not be suitable for severely clogged converters. It’s important to understand that these methods may only provide temporary relief or may not work at all. If your catalytic converter is significantly clogged or damaged, replacing it is often the most effective solution. Note, that using improper methods or additives could potentially cause more harm to the converter or other components of the exhaust system.