I have code P0420. i replaced manifold/cat. code is still there.
upstream o2 completely covered in while chalk stuff (silicone contamination)
i have ordered new up and down o2 but how do i know if this will fix the problem?
is there another problem causing the contamination causing my sensor to fail or did my sensor fail and the residue is from running rich?
I dont recall using any kind of silicone gasket stuff on my car.
I've only ever added a little coolant into the reservoir over say 80k miles.

 

There may be an exhaust leak, which can also throw P0420.

 

that happened on my org manifold. big ol crack in it and i had the 420 code but no exhaust leak now.

 

OEM cat?

 

na, ATP Part # 101122 from RockAuto.com

 

Did you reset the ECU?

Bad O2 sensors are unlikely causes for P0420.

You may want to have the exhaust system smoke tested.

 

you know what? i dont think i did reset the ecu!
i'll try that, thx

 

when i replaced my org manifold/cat the cel went away on it's own soon after i installed the replacement. just fyi
i'll reset the ecu tomorrow. i dont have my tools

 

ok, replaced the upstream o2 and reset ecu. drove not even 3 miles and P1381 popped up.
did some freeway miles. stopped, shut off, restarted back on freeway, refueled, back on freeway. P1381 popped up again after i got off freeway. i felt the engine dip/struggle for a sec and P1381 popped up. parked and i died at idle. started and died started and died. started and gave it gas and she idled. i can also see my gas needle dropping way fast. i'll calculate my mpg tomorrow i can already tell its going to be low.

 

P1381 Cylinder Position Sensor Intermittent Interruption

Time to start troubleshooting the crankshaft position sensor.

 

Is the car running bad withy that code? If not I'd clear it to see If it comes back.

 

i've cleared it and i'ts come back 3 or 4 times. i did some reading in the forums and thought if it runs fine i'll just live with it but i did notice the last time the engine dip/struggle for a sec then the cel came with that code so something is up.

 

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