Question about 2003 Mitsubishi Lancer
Autozone sais its code 0421 catalyst efficency low bank 1
ive noticed the light comes and goes usually after i fill the tank up it turns off wen the gas gets near a quarter of a tank give or take a little the light appears again . and i make sure the gas cap is tight ????
Your number 1 O2 sensor is bad replace it. this is the O2 sensor attached to your headers. Could be faulty sensor or the air/fuel ratio is offset. But replace the sensor its not running effeciently.
Posted on Jan 12, 2009
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Posted on Jan 02, 2017
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