What are the symptoms of a clogged three-way catalytic converter in a car?

[SanLydia]

Specific symptoms are as follows: 1. The car has difficulty accelerating, and it's hard to increase engine RPM and vehicle speed. This is because restricted exhaust flow reduces air intake, leading to decreased engine power. 2. Automatic transmission vehicles experience frequent forced downshifts. Due to exhaust blockage reducing engine power, drivers must press the accelerator harder to get more power output, causing the throttle to open wide. Consequently, the ECU controls the automatic transmission to force downshifts based on the throttle opening status. 3. Slight backfiring occurs during sudden engine acceleration. When engine exhaust flow is restricted, some exhaust gas remains in the cylinders, making the air-fuel mixture leaner and slowing combustion. When the intake valve opens, the mixture is still burning, so the burning mixture can flow back into the intake manifold through the open intake valve, causing backfiring. 4. A 'clattering' sound can be heard from the exhaust system during sudden acceleration or deceleration. This is often a symptom of a damaged three-way catalytic converter, and a broken catalytic converter can easily cause engine exhaust blockage.