Does this happen when the heat is on any setting or just on the defrost setting? I have a similar issue to yours but it's only when the defrost is on and I'm decelerating and it doesn't actually stall. The rpms just bounce up and down some. My AFRs also go really rich when this happens so I'm pretty sure it's a throttle hang issue. Just haven't had a chance to tune it out yet.

 

having same issues over here in kentucky, will try new tune next week hope it fixes it!!