What we can do for auto error code P0171 ?

You can try to do these below :

1.The MAF (Mass Air Flow) Sensor is dirty or faulty Note: The use of "oiled" air filters may cause the MAF to become dirty if the filter is over-oiled. There is also an issue with some vehicles where the MAF sensors leak the silicone potting material used to protect the circuitry.

2.There could be a vacuum leak downstream of the MAF sensor

3.Possible cracked vacuum or PCV line/connection

4.Faulty or stuck open PCV valve

5.Failed or faulty oxygen sensor (bank 1, sensor 1)

6.Sticking/plugged or failed fuel injector

7.Low fuel pressure (possible plugged/dirty fuel filter!)

8.Exhaust leak between engine and first oxygen sensor.

Of course, this is not completed list. You can add your versions in comments.
Learn more: https://www.obd-codes.com/p0171

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