1999 Ford Expedition OBDII code-P0171

1999 FORD EXPEDITION
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DOUBLE R1959
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Engine Performance problem
1999 Ford Expedition V8 Four Wheel Drive Automatic

new motor. left bank too lean. What should I check to fix.
Aug 27, 2009 at 12:09 AM
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2CARPRO JACK
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Vacuum leaks first.Check the rubber fitting where the PCV line attaches to the intake manifold, those always deterriorate and cause vacuum leaks.Check fuel pressure. May also be a bad Mass Airflow Meter, Fords have issues with them andthey will set a P0171, if you continue to drive it will usually set a P0174 (lean bank 2)as well as the P0171
Aug 27, 2009 at 12:47 AM
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