1996 Ford Contour check engine light is on and I checked th

DOGROCKSTER

MEMBER
1996 FORD CONTOUR
4 CYL
FWD
AUTOMATIC
105,000 MILES

It gave me the two codes po135-oxygen sensor heat bank 1 sensor 1 and the code po420 - bank 1 catalyst efficency below limit what is this and o2 sensor or maybe an egr valve that is bad anyone know what it is because I went from almost 28 miles to the gallon and now I am at about 12 if I wanted 12 I would drive my 3/4 ton chevy someone plz help

Tuesday, December 29th, 2009 AT 2:48 PM

1 Reply

MERLIN2021

MECHANIC
17,250 POSTS

First parts to replace are the 02 sensors, these are made to give 100,000 miles of service and you are a tad over, P0135 for bak1 sensor1 is the first 02 sensor on the #1 cylender side, I recommend replacing ALL 02 sensors at this point, P0420 we hope is being set by lazy 02 sensors, your car has 2 02 sensors one befor the converter and one after, these should switch quickly one the front sensor and remain almost flat one the back sensor, If 02 readings are not right, you will get poor fuel mileage, and could be the reason for the efficiency code too.

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Tuesday, December 29th, 2009 AT 3:13 PM