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1999 Ford F-250 diagnostic codes - "system lean"

Tiny
DUKELOWELL
  • MEMBER
  • 1999 FORD F-250
  • V8
  • 4WD
  • AUTOMATIC
  • 147,000 MILES
I have a 1999 F250 that I've had for a little over a year. Runs great, no complaints. Yesterday my "service engine soon" light came on. Took it in for service and they read the codes (PO171 & PO174) which indicate system lean left bank and system lean right bank. How do I fix this?
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Friday, September 3rd, 2010 AT 6:17 PM

1 Reply

Tiny
RASMATAZ
  • MECHANIC
  • 75,992 POSTS
Lean fuel condition could be caused by one of the following below:

1. Vacuum leaks
2. EGR and PCV valve.
3. Low fuel pressure.
4. Dirty fuel injectors.
5. Mass Air Flow Sensor.
6. Oxygen Sensor.
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Saturday, September 4th, 2010 AT 2:56 PM

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