failed smog because lean code p1071

2001 FORD EXPLORER
193,823 MILES • 2WD • AUTOMATIC
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JIMMYJAMES1234
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  • 1 POST
We have had a new fuel pump,MAF sensor, o2 sensor and new exhaust gaskets on it. What else could be the problem?
May 24, 2016 at 10:39 AM
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JACOBANDNICKOLAS
  • ✓Experienced Mechanic
  • 110,236 POSTS
Most lean mixture codes are caused by a vacuum leak on the engine. That is where I would start. If you have access to a vacuum gauge, place it on any of the intake vacuum ports and start the engine. Vacuum should be around 18 pounds at idle. Also, if you have access to a scanner that can read real time live data, it would be helpful to see what the short term trim readings are. Let me know what you find.
May 24, 2016 at 11:32 AM
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