2003 Pontiac Vibe Catalytic Converter

The platinum group metals burn up excess fuel in the catalytic coverter. Scrap large gm converters are worth $75 aftermarket converters are worth $5 aftemakets have alot less platinum in them. The o2 sensor takes a readind before and after from two diffrent sensors the diffrence between those two are the efficiency. So faulty o2 sensors is less likely than a aftermarket converter