Kevin Baker

In my attempt to answer, what I was "supposing" was that there is not a problem with the way the vehicle is running, more a problem with the way the tests were run. I've been doing this for a couple of years, and have found that if the rpm's are closer to the low end of the test scale, you can have poor NOx results. That is why I was asking for more info, like what the test rpm's were compared to what the acceptable rpm range for the test was, as well as what the O2 number were. If the O2 sensor has gone south, your O2 numbers will be out of whack. Further, if the station has not recently had their test gasses checked, by the state, they could have a NOx reading that is artificially high. I've had my station fail and had to replace the test gas clyinders.