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Idahome
Joined: Wed May 2nd, 2018
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Is this a 4 cyl? 3.0 or 4.0?
P0171 means a lean condition only in one bank, one side of the engine
Typically that usually rules out anything that effects both sides of the engine like the MAS, intake air leaks, etc since they would effect both sides, typically, not always. The Po174 code may not be far behind
Lean condition means the computer has seen more 02 in the exhaust on that bank then expected and it has already tried to correct it by adding more fuel, still the condition is lean. It has occurred enough times to set a code.
With those miles and the work you have done I would suspect:
failing injector
wiring at the 02 sensors you replaced (always good to go back and check the work you have done)
exhaust leak on bank 1 side
or failing pcv valve (but again that usually effects both sides)
Cleaning the MAS NEVER HURTS
from OBD2.com:
"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.
There could be a vacuum leak downstream of the MAF sensor
Possible cracked vacuum or PCV line/connection
Faulty or stuck open PCV valve
Failed or faulty oxygen sensor (bank 1, sensor 1)
Sticking/plugged or failed fuel injector
Low fuel pressure (possible plugged/dirty fuel filter!)
Exhaust leak between engine and first oxygen sensor
Read more at:
https://www.obd-codes.com/p0171
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