2003 Jeep Laredo O2 sensors

2003 JEEP GRAND CHEROKEE LAREDO
63,000 MILES • 6 CYL • 4WD • AUTOMATIC
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FROSSI
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Code PO138,PO139. Replace rear downstream sensor due to wear through the isulation in the wire and reset the codes. Four days later another code of PO139, Haynes manual says O2 1/1 Slow Response. All four sensors seem to test ok when taken out and heated with torch as far as putting out voltage. Witch sensor is now the problem?
Oct 26, 2009 at 10:21 PM
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JACOBANDNICKOLAS
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What size engine do you have?
Nov 9, 2009 at 9:41 AM