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o2 converter

  1. ('06-'08) 2007 - O2 converter (P0420) / head gasket leak?

    Problems, Maintenance, and Warranty
    Hi my high mileage (443K km) Forester has been throwing a check engine code for a while now. Got it read and it was P0420 - Catalyst System Efficiency below Threshold, Bank 1. My mechanic just called and 1) noted the head gasket leak is much worse than previous); 2) cylinder 3 is misfiring; and...
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