I just had the dealer replace my plugs and air filter under the free maintenance, my car has 47k miles. It shivers while idling at times and when it does, the exhaust makes a soft thumping sound. It always idled silky smooth before the plugs were changed. I called the dealer, the SM said to bring them the car when possible and they will check for codes. I am paying a lot to own this car and it is so frustrating when the service manager acts like I should just get used to it and tells you there is likely nothing wrong with the car.
