I have 80000 miles on my 300 in February I was down south and was told I had a miss fire on #3 and had all coil pics and spark plugs replaced for the ride home it ran perfect and has till about a week ago it started to miss fire again #3 so took it to my dealer they said cylinder head needs replaced plus some other parts total damages about 4300 are you serious I have always babies this car and had it serviced regularly I bought it in 2017 is this really happening