The cat. Converter is part of the emissions system, if it clogs up than it can cause serious damage to the engine. Your mechanic is right, it could be a faulty oxygen sensor making the air/fuel mix wrong which in turn causes the converter to get clogged up because it can't do it's job properly if the o2 sensor is not doing its job properly. A dirty fuel filter can also cause it and that would be a very simple replacement procedure and filter should only cost $10 or $15.
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Tuesday, September 21st, 2010 AT 5:41 PM