Soot on sensor

2002 TOYOTA TACOMA
181,700 MILES • 3.4L • V6 • 2WD • AUTOMATIC
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MEAGAN SENKBEIL CARSTENS
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I had multiple codes thrown in the last two months. Codes: P0171, P0171p, P1131, P1135.
I have changed the sensor, cleaned the mass airflow sensor, changed out a few questionable hoses, new filter, cleaned the throttle intake and air boot.
Ran super rough the next day over heated and threw the P1135 again. Took off the sensor and it was covered in soot. Put the original one back on to return it and get a new one. turned on the truck and did nott make it out of the driveway. Now there is soot on both sensors.
I am wondering if I now need to take off the manifold and clean that or just replace the sensor? The throttle body was dirty but now it is clean. I am completely confused and thrown of what I should do next. But I am wondering how the soot is going from the throttle body to the sensor?
Apr 29, 2017 at 11:26 AM
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CARADIODOC
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Those are oxygen sensors. The soot is the symptom, not the cause of the problem. The engine is burning too much fuel. Common causes of that are fuel pressure that's too high, and a spark-related misfire. The misfire would result in the rough running you described. Spark plugs and wires are the place to start.
May 1, 2017 at 7:37 PM