The day before I was due to go on a 2000 mile trip with my ’94 the Check Engine light came on. I dropped by the local dealer to pull the code. It indicated an O2 sensor needed to be replaced, but it was on backorder with no way of getting to me before the trip. They assured me it would be ok to drive that distance, so I planned to have the work done when I got back. During the trip the light went out. So here’s the question. Does it simply reset or has the computer stopped sensing the problem?