Interesting. While the following is probably not the case with your Spark, it was with mine.
I bought a used 2016 Spark (21k mies) last Spring. It started rattling after a month. Rattled mostly at certain RPMs and it was consistent.
I initially thought it was a heat shield, then the right rear door. It was kind of hard to judge just where it was coming from.
After a few months of this, I finally booked an appointment to take it to the dealer for a broken driver's door lock and the 2 recalls. When I made the appointment, the mysterious 'rattle' was also on the list of thi