Sometimes my 97 throws a code for a bad front right heated O2 sensor, but it only throws the light during extended highway driving - usually after about, like, eight hours. A couple times now I've just reset the ECU and it's gone away until the next time I had to drive eight hours.

Sounds more like a loose connection to me than a dead sensor. Thoughts?

 

its a bad sensor....mine throws a code when its above 40 degrees.....its goes off for the winter until it gets warm out.....inspection is in winter too