Catalytic Converter

What it does

The catalytic converter is your exhaust's air-cleaner. As exhaust passes through, a honeycomb coated in precious metals turns nasty gases into mostly harmless ones. It rarely dies on its own — it usually gets poisoned by an upstream problem like a long-running misfire or oil burning, which clogs or melts the honeycomb. Fix the cause first, or the new converter dies too.