Looking for advice. 2020 M340i, Bought the car 1 week ago, driving home today. Pulled up to a traffic light, car felt like it was going to cut out. Nursed it the 1mile home on reduced power. Codes read as misfire on cylinder 4. What do we think repairs will cost? Already wrote to garage telling them I’m in 2 minds to return the car for a refund as it’s soured the purchase