I have a 1998 Chevy P/U, 1500, 5.7. My scan tool reads PO420 - which is catalyst system efficiency below threshold (bank 1) Can you explain what that means and how to repair it? Thank You - Robert Norris
I have a 1998 Chevy P/U, 1500, 5.7. My scan tool reads PO420 - which is catalyst system efficiency below threshold (bank 1) Can you explain what that means and how to repair it? Thank You - Robert Norris
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