Often, a visual inspection will reveal that your Infiniti spark plug wires are in need of repair. Open your hood and inspect your Infiniti spark plug wires for signs of damage such as a cut, grooves or marks from chafing or scorch marks from burning. If you see the latter, there might be arcing in your engine, which is caused by leaking electricity. These spark plug wires should be replaced immediately as a matter of safety. Sometimes the indications of Infiniti spark plug wire deterioration requires a little bit more detective work. If you have an ohm meter, you can measure the plug wires resistance from end to end and see if they are within specifications established by your Infiniti owner's manual. You can test the resistance level for your Infiniti by first checking the factory service manual for your car, where you can find a resistance rating for the spark plug wires. If a spark plug wire has a totally bad core - which means that there's a virtual separation of the conductor-the resistance from one end to the other will be very close to infinity. In most cars, spark plug wires have a resistance of 10,000 to 15,000 ohms per foot of length. Be aware that some after-market replacements may claim to work for a wide range of vehicles, but they may not be a good match for your vehicle.  So purchase your Infiniti spark plug wires from recognized brand-name manufacturers here.