Spark plug wires must be checked according to the recommended times and whenever replacing the new spark plugs in the engine. First, physically examine the spark plug wires with the engine operating in a dark garage with sufficient air flow; check the plug wire attaching ends individually, being careful not to touch them against any moving engine components. In case the wire is broken, a short or a slight spark will appear at the faulty point creating the necessity of replacing the wires after the engine has cooled down. After removing the negative cable to the battery, one should check each wire individually so that they are not confused with the order, which is important to ensure that the engine can work properly. Unplug the plug wire to the spark plug with a removal tool or by twisting and pulling the plastic boot, but not the wire. Check the boot inside with a feeling of the corrosion, then re-insert and stretch the wire and boot back into the spark plug, with a tight fit otherwise, crimp the metal connector in the boot with a pliers. Wipe all the length of the wire with a clean rag to remove dirt and grease and ensure that there are no burns, cracks, and other damage but without bending it too much. Take the wire off the distributor, ensuring that there is no corrosion, a tight fit and then replace it. Check the rest of the spark plug wires to make sure that they are tightly fitted at the distributor and the spark plug. In case new spark plug wires are required, they come as a set of wires, and the plug wires are removed and installed sequentially, to prevent confusion in firing order. Check the distributor cap and rotor (worn parts) by loosening the screws and removing the distributor cap to check wear or signs of carbon tracks and worn/loose contacts; replace parts with new parts in case of wear or find signs of carbon tracks or worn contacts, and it is a common practice to change the distributor cap and rotor when new spark plug wires are being fitted, ensure to transfer the wires in the same sequence as the old distribution cap to the new one to avoid firing the wires in the wrong order.