1999 Jeep Cherokee


T Boyer

July, 23, 2009 AT 3:45 PM

Engine Performance problem
1999 Jeep Cherokee 6 cyl Four Wheel Drive Automatic 140000 miles

I have a re-occuring trouble code 171 bank 1 lean. I have replaced the exaust manifold because it was cracked, some of the vacuum lines (dry rotted) and the up stream O2 sensor. Could a clogged fuel filter give this code or maybe a bad fuel regulator?


1 Answer



July, 23, 2009 AT 11:35 PM

1999 Jeep Cherokee Trouble Code 0171

A lean fuel condition can be caused by: * Low fuel pressure due to a weak pump or leaky fuel pressure regulator. (Use a fuel pressure gauge 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 gauge 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)

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