I was driving my car really slow (maybe 10 mph) the other day with the windows open and I heard this medium-loud "pop" sound coming from somewhere in the back, and then I smelled a burning smell, not too strong. The car is driving perfectly fine, but whenever I'm stopped in traffic I smell the burning smell again, which makes me think it smells like that all the time and it just blows away when I'm actually moving. This actually happened on the way to the dealership for service, so I had them look at it and all they said was that they couldn't "replicate the pop sound". I don't think they spent too much time on it though. So, does anyone have any ideas as to what this could have been?