Help codes p0171 and p0172 Fuel Trim Malfunction

Discussion in 'SN95 4.6L Mustang Tech' started by v8carnut, Nov 12, 2005.


  1. v8carnut

    v8carnut New Member

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    Check engine light came on. I pulled the codes and get p0171 and p0172 Fuel Trim Malfunction. It starts and runs rough at idle and misses at about 1200 RPM. Any ideas??
     
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  2. 87AODGT

    87AODGT Founding Member

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    p0171 is system lean and 0172 is system too rich, maybe a set of 02 sensors that are shot and sending the computer bad signals
     
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  3. v8carnut

    v8carnut New Member

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    The codes are kinda vague I’ll change the o2’s I’m sure they could use it anyway. Thanks!
     
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  4. v8carnut

    v8carnut New Member

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    OK I’m stupid I found the culprit , frick’n vacuum line… plugged it back in and she’s running sweat again.. and I dnd’t spend any money either.. Yee Haa :banana:
     
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