It has also been cold and foggy a lot around my house lately. I have also been experiencing odd power surges under various throttle conditions, but most noticeably in 2nd gear. I could swear the backfiring sound is happening, but I usually don't hear it b/c of my stereo. It has been happening a lot lately. Let us know how it goes with the dealer and the update if you get it. I am very curious to see if is the update or the possible condensation.