I'll probably catch some flack from a poster, because it goes against scientific theory, but as an electronics technician for ten years in a previous life, I learned it is just theory. At any rate a guy who lives in the south bay had the same problem on about the same car. As he and the mechanic were cruising the Santa Cruz Mountains, he noticed the temp was running high. The radiator was changed for suspected restricted flow. That not only solved the heating problem, but NOX went from 800 ppm to way less than 100 ppm.

__________________
Auto Zentral Ltd.