Thread: PO 420 code
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Old 05-21-2007, 02:18 AM
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Re: PO 420 code

Quote:
A engine running rich will do the same thing if cat is overloaded from rich fuel.
If the average V. on the front sensor is around 450mV wouldn't this indicate that the engine mixture is OK, and I can procede with the test.

Quote:
A miss fire ,poor tune up or rich running engine is one of the main causes of cat codes and failed cats
He did have bad O2 sensors originally, and he said the engine was sluggish when he accelerated fast (before changing sensors). Is it possible the bad O2 sensors caused his engine to run rich and that caused his cat. conv. to go bad.

I'll probably do the tests tomorrow and post the results.
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