Poor running, codes P0171 and P0172

2003 SATURN L200
174,000 MILES • 2.2L • 4 CYL • 2WD • AUTOMATIC
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CINDERS58
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Car listed above is a lw 200. I am experiencing rough idle at red light, cooling fan on. Codes P0171 and P0172 at the same time. Fuel system closed loop, long term fuel trim -10.94%, short term 1.56%; bank 1, RPM 2105.0.
Jun 9, 2018 at 12:27 PM
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JACOBANDNICKOLAS
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Hi and thanks for using 2CarPros.com.

After reading your post, it sounds like the O2 sensor itself if bad. When running in a closed loop at start up, the system runs a predetermined fuel mixture which does not involve the sensors until it goes open. Most times when a sensor goes bad, it stops working completely forcing the computer to run closed loop again. However, I have seen them send incorrect data to the computer also.

I noted that you only mentioned closed loop running. If that is all it is doing, my first guess would be the sensor itself or wiring to the sensor. Have you replaced the sensor at this point?

Let me know,
Joe
Jun 10, 2018 at 6:27 PM