I replaced the no-name universal O2 sensor with a Bosch that has the correct electrical fitting to plug into the car's wiring harness and it solved my problem. I cleared the code and the CEL light has stayed off for over 1,000 miles. Better still, I made two 600 mile trips since then and the milage is up a bit, 23.5 mpg vrs. a former best reading of 22.3 mpg. Plus I made the exact same trip the week before, with the defective O2 sensor in place and got 19.4.
The no-name universal came from an eBay seller in a box that was not marked as to the country of origin, but I suspect it was China. It's a good supplier & brand to avoid -
carpartswholesale
carpa