1997 Jeep TJ OBD Code P0171 Too Lean Mixture

1997 JEEP WRANGLER TJ
90,000 MILES • 6 CYL • 4WD • MANUAL
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MNURUDDIN
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I recently started getting very poor gas mileage. Less than 10 mile per gallon. I get a P0171 code when I hook up a code reader.

Where should I look for a the problem. Oxygen Sensor? Vacuum Leak? Somewhere else?
Mar 21, 2009 at 10:50 AM
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MERLIN2021
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You may have a vacuum leak, get a can of spray throttle body cleaner, spray the vac lines and maniflod area, when the idle changes, youve found the leak! You want the engine running and spray on the outside but do direct the stream onto the hoses, if it is a vacuum leak, the engine idle will change speed, then you have detected a leak, repair the vacuum leak and see how it runs!
The 02 sensor may also be bad they are said to be 100,000 mile parts, your close to that, MAF and leaks in the air duct system can cause unmetered air to bypass the MAF, causing the PCM to add more fuel to compensate. I can send a PDF on vacuum leak detection using scan tools, but I need an email address.
Mar 21, 2009 at 11:00 AM
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MNURUDDIN
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Please send the PDF on Vacuum Leak Detection to mnuruddin@cfl.rr.com
Mar 21, 2009 at 2:48 PM
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MERLIN2021
  • ✓ASE Certified Mechanic
  • 17,250 POSTS
  • ASE Certified Mechanic
Sent!
Mar 22, 2009 at 10:37 AM
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