I recently purchased a 2011 328i xDrive with ~46,000 miles. It's been an incredible car so far but I have had an occasional timing issue. Often when I accelerate heavily, especially when kickdown is initiated, the SES light comes on and the engine rumbles and sounds like it is misfiring and running a couple cylinders down. I stop immediately, turn my car off and restart it and the engine is running normal again. I have done some research and it seems to be a spark plug/ coil issue. Are there any other possible causes for this problem and if it is a spark plug/ coil problem, around how much will it cost to fix. Thank you
