O2 sensors usually go a minimum of 80-100k, yours went a little early or at least indicated that it did. Check your engine air filter, when those get dirty, gunk can build up on the MAF (mass air flow sensor and you need a special spray to clean it off as it gives a bad reading to the PCM about the 02 status. You got off lucky, good for you, check that filter and connections up to the MAF especially if you drive in dusty conditions.

 

Will do, re: checking the air filter. Thanks again.

 

This *may* be covered under the emissions warranty.