I think something changed in the tune. Any low voltage or long time sitting for the car? Admittedly, this was a generation ago, but on the GTO I experienced a partial reversion to the stock tune after a low voltage incident (this is supposed to be impossible, but nevertheless it happened). With a long distance retune everything resolved. Either that or the sensor itself is bad. Somehow, the computer is reading code telling it to clip your wings because of the data from that sensor - either the sensor is sending wrong data, or a part of the programming is responding when it should be (and may have been formerly) deactivated or modified by the tune (or the physical structure of the computer was damaged / changed - this was what it looked like at one point on that GTO but turned out the ECM was not damaged). Just my two cents - I'm not a HC specialist like these other guys by any means, however. Hope you can get it corrected without any major drama.