2007 Chrysler PT Cruiser Owner Manual - Page 368

368 MAINTAINING YOUR VEHICLE Spark Plugs Spark plugs must fire properly to assure engine performance and emission control. New plugs should be installed at the specified mileage. The entire set should be replaced if there is any malfunction due to a faulty spark plug. Refer to the Engine data Label located under the hood for the proper type of spark plug for use in your vehicle. Ignition Wiring System The ignition cables should be kept clean and properly connected. Terminals should be fully seated. Cracked, damaged, or faulty cables should be replaced. Catalytic Converter The catalytic converter requires the use of unleaded fuel only. Leaded gasoline will destroy the effectiveness of the catalyst as an emission control device. Under normal operating conditions, the catalytic converter will not require maintenance. However, it is important to keep the engine properly tuned to assure proper catalyst operation and prevent possible catalyst damage. CAUTION! Damage to the catalytic converter can result if your vehicle is not kept in proper operating condition. In the event of engine malfunction, particularly involving engine misfire or other apparent loss of performance, have your vehicle serviced promptly. Continued operation of your vehicle with a severe malfunction could cause the converter to overheat, resulting in possible damage to the converter and the vehicle.