Has your "Service Engine Soon" light come on? Your car has an on board computer that has a 16 pin diagnostic socket under the dashboard that should identify which cylinder is creating the misfire. Your car ha one ignition coil per cylinder, an ignition coil or spark plug may be failing or a fuel injector may be failing. Even if the light is not illuminated a "pending code" may be stored in the computer. A scan tool is required to retrieve codes from the on board computer.