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O2 Codes after header install

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Old Mar 13, 2004 | 05:13 PM
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Default O2 Codes after header install

I have some strange behavior after the header install on my 98 convertible. I am getting the following codes:

P0134 HO2S Circuit Insufficient Activity Bank 1 Sensor
P0155 HO2S Heater Circuit Bank 2 Sensor 1
P0134 HO2S Circuit Insufficient Activity Bank 1 Sensor
P0134 HO2S Circuit Insufficient Activity Bank 1 Sensor
P0155 HO2S Heater Circuit Bank 2 Sensor 1

I also notice that on one side, the front O2 is reading about 350mV and on the other about 100 mV. It is consistent after the car is warmed up. When I romp on it, the high side numbers go down but the low side number goes up. I am assuming that the codes indicate that something isn't normal but I don't know enough to tell what.

What was done was a set of headers, high flow cats, and rear O2 extentions. Could it be something simple like a bad wire or bad O2 sensor (hoping)!

Chuck
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Old Mar 14, 2004 | 07:46 PM
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yeah prob o2, i always get heater codes when my car is cold. im gonna try some new o2s and see i think they are goin bad anyway but 02 codes common after headers, just try a new set
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Old Mar 14, 2004 | 09:54 PM
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Thanks. I'll try a new set of O2 sensors. - Chuck
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Old Mar 14, 2004 | 09:58 PM
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hows your gas mileage btw? usually when u see that drop off it means the o2s might be crapping out
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Old Mar 15, 2004 | 06:52 AM
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i got P0135 randomly. I think its the extensions, never happened EVER before the headers and thats the logic i'm gonna work since its only one bank. Maybe swap the whole extension over first and look for P0134. Then figure out whats happening.

Mostly on cold days, but did happen once on warmer day (50). Humidity was always very high. Maybe i need to use some dielectric grease on the heater wires (which are those?).

i do have 70K on the sensors so i won't rule that out but i'm thinking extensions first.
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