2004 gmc

2004 GMC SIERRA
44,758 MILES • 6 CYL • 2WD • AUTOMATIC
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WOLFDOG
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I have check engine light code p10172-p10175 engine runs rich.bad gas mileage.change mass air flow sensor did not help. any suggestions thanks
Jan 16, 2011 at 7:58 PM
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RASMATAZ
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Probable causes of an engine running rich are as follows:

1.Excessive fuel pressure can be cause by restricted fuel return line
2.Defective Oxygen Sensors.
3.Leaking injectors and fuel pressure regulator.
4.Coolant temperature sensor out of calibration.
5.Restricted air intake system.
Mar 16, 2011 at 2:39 AM