Check Engine Code P1131

[BeachRunner]

'97 Explorer Sport 4x4, my check engine light likes to come on about once per week, it stays on about a day, then goes off again. When we caught it on once, we took it to AutoZone who diagnosed code P1131, "lack of HO2S switch - sensor indicates lean". Greek to me... I hear there are about three oxygen sensors, so what exactly needs replaced? I'd rather my husband try the fix rather than pay a dealer the big bucks!

 

[Runnin'OnEmpty]

Beachrunner, the 31 in the code indicates it's an upstream sensor. I'm not sure how many O2's are on your model, but look for a sensor that is in front of the catalytic converter, mounted in the exhaust pipe. It's been my experience that O2 sensors only last around 60-80K miles, so I would replace it. Good luck.