how to know if catalytic converter is bad

5 Hidden Signs Your Catalytic Converter Is Dying The once-thriving vehicle of your dreams is now coughing, sputtering, and wheezing its way through the city streets. Its exhaust system, once a powerful and efficient purveyor of emissions-free air, is now a ticking time bomb, ready to unleash a toxic cocktail of pollutants into the atmosphere. … Read more