1997 Ford F-150 bank 1 lean

  • 1997 FORD F-150

Engine Performance problem
1997 Ford F150 6 cyl Two Wheel Drive Automatic 120000 miles

THe truck has had the spark plugs and wires changed, fuel filter changed and it is now saying bank one lean, and it smells like gas and runs rough would this be the o2 sensor or something else

Do you
have the same problem?
Monday, September 22nd, 2008 AT 9:22 PM

1 Reply


Could be it but others will do that too

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)

* TIP: On many Fords, a P0171 and/or P0174 Lean Code may sometimes appear because of a bad Differential Pressure Sensor (DPFE). This sensor monitors EGR flow, and is located on the engine near the EGR valve. There are two hoses that connect the sensor to the tube that runs from the exhaust manifold to the EGR valve. The sensor misreads EGR flow and the computer increases EGR which has a leaning effect on the fuel mixture. The fix is to replace the DPFE sensor.

Was this
Monday, September 22nd, 2008 AT 10:02 PM

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