hackish -
I have worried about the same thing. On the chance that your data confirms your hypothesis, that is one reason I converted my non-heated 02 sensor to a heated version :
http://ecomodder.com/forum/showthrea...2-a-10921.html
But like everyone else says, the VX lean-burn mode is a special case, and we need to see the data. A comma-delimited output in the "code" editing wrapper would help a lot for independent analysis.
CarloSW2