Probably one of the coil packs for the spark-plug. I’ve had this happen twice. Relatively easy and inexpensive fix. For $80 you can get a four-pack of ignition coils of good coils (just swap them all out on the car while you have to tools out. I swapped only the one that was misfiring and a week later a different original coil started to fail.) Shouldn’t take more than 20 minutes or so (unless you are like me. it SHOULD take 20 minutes . . . end up being triple that time).
Way cheaper this way as well, dealer said they would do it for $450 for 1 coil. An OBII Reader BlueTooth is how I found out what was going on. Another $80, BUT you learn much more about your car and if the mechanic is taking you for a ride