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david, Auto Service Technician
Category: Car
Satisfied Customers: 1500
Experience:  Certified Master Technician,Certified in diesel & gasoline engines
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Infinity g20: 2000 with a po171 code (fuel system lean bank 1 - what

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I have an infinity g20 2000 with a po171 code (fuel system lean bank 1 - what are the most common causes

Basically this means that an oxygen sensor in bank 1 detected a lean condition (too much oxygen in the exhaust).

Fuel system lean bank 1 condition can be caused by:
Low fuel pressure due to a weak pump or leaky fuel pressure regulator.
(use a fuel pressure gage to check fuel pressure at idle)

Dirty fuel injectors. (try cleaning the injectors)

Vacuum leaks at the intake manifold, vacuum hose connections or throttle body. (Use a vacuum gage to check for low intake vacuum)

Leaky EGR valve. (Check operation of EGR valve)

Leaky PCV Valve or hose. (check valve and hose connections)

Dirty or defective Mass Airflow Sensor (MAF). (Try cleaning the MAF sensor wires or filament with aerosol electronics cleaner.

Do NOT use anything else to clean the sensor, and do not touch the sensor wires)

In the vast majority of cases, simply cleaning the MAF sensor does the trick.

The mass air flow sensor is located in the intake air duct.

Hope this helps
Good luck
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