This has been going on for quite a few years now, but thought I'd try to find a direction to look. The check engine light comes on when the ambient temperature gets above 45 or so, but in the winter when it drops down around freezing or so, it goes off and stays off until it warms up to 45-50 again. Truck starts and runs the same, gas mileage is the same, nothing noticeable changes wit the light on or off. Being a '94, it's pre OBD2, and the only thing I could gather from the analog volt meter check was maybe an O2 sensor. But not real sure on that and don't have a working analog meter anymore.
Have never heard of an O2 sensor that worked or didn't work due to outside temperature. Anybody experience this problem before? And if so, what was it?