Mechanics

CHECK ENGINE LIGHT IS ON

1996 Mercury Mystique

Engine Performance problem
1996 Mercury Mystique 6 cyl Four Wheel Drive Automatic 89000 miles

Hi I had a diagnostic run on my car and it indicated the code for a fault in the upstream oxygen sensor but I had already replaced but didn't have the code erased. After having that done it came back on again and again it showed a default in the sensor so I had it exchanged for a new one figuring the other was defected but the light still comes on. The only code indicated in the diagnostic is for that sensor. Is there something else it could be that would cause it to indicate the sensor? Thank you.
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Lilstinker12
May 25, 2009.



I have the same problem with my 95 V-6 since I drove it from the used-car dealer. They said they diagnosed an oxygen sensor fault and replaced it but it still comes on sporadically then goes off. There is some hesitation or vibration that occurs occasionally at various speeds that either comes from the transmission or engine. I wonder if these are fixable or gremlins that we just have to live with.

Tiny
William1953
Jun 19, 2009.
Actually I resolved the problem and perhaps it is the same for you. Check the wires on the harness that the oxygen sensor connects to. It turns out that one of the wires on my car somehow split so I spliced it back together and the engine light is now offfffff lol thanks

Tiny
Lilstinker12
Jun 19, 2009.