Just started hearing this noise from the left exhaust pipe Sunday. Less smoke comes out of it. Has only happened Sunday at night after driving 8 miles home from work. I’m in the Chicagoland. So cold winters and nights. Just happened again today right before an oil change. Temperature was mid teens during the day. Of course it didn’t do it when I brought out the mechanic. Dealership is going to charge me diagnostic fee $180. It’s leased and just coming up on 6k miles.

please help