I have the same thing right now. It smells like exhaust/unburned off gas. Worse when stopped at idle with the cold it being really cold. 2014 Chevy Silverado. Did you figure out the problem?
Lmao you guys are all great. This was drivong me nuts. Actually I was driving with nuts in my 2014 Silverado after changing the cab filter but I removed the blower motor grabbed my nuts out and now I am back in business.