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Old 04-04-2017, 11:25 PM
Tech II Tech II is offline
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Re: 2002 Regal Ls OBD code PO420

Car is 15 years old......I would replace the sensors, if original.....

Beware of some aftermarket cats.....I have seen cars come in with cats half the size of the original, and the customer wonders why the car is not passing emissions......

Also make sure there is no engine problem taking the cat out.....but chances are, if original cat, it has outlived it's useful lifetime....
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