Q: catalytic converter going bad does it need to be replaced?

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So my cat is going bad and a check engine light came on. As of now, there is no white smoke from my exhaust but I can tell there has been a performance drop. Do I need to replace this right away? I do not need to pass smog until next year sometime.

My car has 129000 miles.
My car has an automatic transmission.

The catalyst should be replaced as soon as possible if it is bad. The backpressure on the engine will cause the engine to run with less power and may overheat the engine valves resulting in engine damage. the catalyst can be tested for excessive backpressure with a pressure tester put in the O2 sensor hole near the manifold. This verifies the catalyst is bad and not an O2 sensor after the catalyst is defective.

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Hi there. The biggest issue with not replacing a damaged catalytic converter is that it will progressively create excessive build-up of carbon deposits further up the exhaust system. Eventually it will start building up on valves and can cause serious engine damage if not replaced.

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