i had to have a used motor put in my 01 XJ and apparently the peopel i got the motor gave me the wrong motor. and now im getting a random misfire code. the plugs and the whole coil pack have been replaced and its still there. so i took it in and i was told its the wrong head for my year of jeep so i need to find out where to find out where i can look to find out what year that motor is so i can put the right coil pack on it. any idea guys?