so i had to go pick up granny this mornin and it was about -13 C i was stupid and did not plug it in last night. i plugged it in for about 1 hour before i left. it was still cold though. i was in a rush so i only gave it about 15 min to warm up. i had some black smoke while pullin out of the garage. i have never had black smoke before. i look for it everytime and never. is this just a result of a very cold start or should i begin to stress ?