My Cruze has been awesome in its first 10k miles but lately has developed some weird behavior. In the last 700 or so miles its done five regens, or what I assume are regens. In each case when I come to a stop at a light or elsewhere the idle surges very noticeably. This always coincides with the fan running after I shut it off, and decreased mpg, hence I assume the regens. The rest of the time idle is normal. I never experienced the surging once during the first 10k miles; only noticed the fan running after shutdown a couple times. There are no codes and everything else about driving feels totally normal. Is this possibly just happening because I've been doing more short drives with stoplights, combined with winter cold and winter fuel? I'm still getting just under 45 mpg for mostly local short trips and 60+ when on the highway. Has anyone else had this happen? I tried taking some advice from searches here and keeping the rpms up under load during the last time I felt the regen "symptoms" but 100 miles later, it just did another one. Do I need to take it in for a manual regen? Or just keep trying to drive it a little harder and do some highway runs? Would a fuel additive help at all?