Usually its plugs, loose crank bolt or an air leak somewhere that will set a missfire code. Coils are a possibility also.
Check the crank bolt first, then go on to look for air leaks. To tell if it has an air leak, have the long term adaptive checked (any dealer or friend with auto tap, raptor or xcal2 can do this) if it is more than +\- 6% you have a problem.
Then if that isnt it, check the plugs and then check the coils. Change 1 coil at a time until it doesnt set the code any more. (just use 1 or 2 new coils and move them around)
Check the crank bolt first, then go on to look for air leaks. To tell if it has an air leak, have the long term adaptive checked (any dealer or friend with auto tap, raptor or xcal2 can do this) if it is more than +\- 6% you have a problem.
Then if that isnt it, check the plugs and then check the coils. Change 1 coil at a time until it doesnt set the code any more. (just use 1 or 2 new coils and move them around)