The first sign that your Infiniti catalytic converter is failing may be an indicator light flashing on your dashboard. Perhaps you noticed some performance problems while driving, such as hesitation when you pressed the gas pedal. Your fuel mileage was dropping. Ultimately, a failed catalytic converter will kill the engine because of the blocked flow of exhaust gas that travels back up into the engine. Unfortunately, all of the symptoms of catalytic converter failure are also symptoms of other component failure in the exhaust system. And, the catalytic converter usually fails because of a failure in another part of the combustion or exhaust system, which clouds diagnosis even more. To diagnose whether your Infiniti catalytic converter is indeed to blame, check your onboard diagnostic system. Sometimes the interior core of the catalytic converter will break loose within the unit; you can test that when you hear rattling noises as you pound your fist on the converter. Using a laser pyrometer, which can measure very high temperatures, check the heat levels of the inlet and outlet areas of the catalytic converter. If the cat is working correctly, the inlet will be much hotter than the outlet. If the exhaust system is clogged, confirm it with a pressure tester. Disconnect the intermediate exhaust pipe from the catalytic converter, and run the engine to see if everything runs smoothly. If you need to replace your cat, then purchase a high-quality Infiniti catalytic converter from our site.