To test a coil pack, use an ohm meter to check for continuity, ensuring that the ohm values are accurate. Buy a Chilton?s or Haynes manual to determine the appropriate mega ohms reading on the coil pack, or search for the information online.
Loss of fire or spark in the cylinder typically indicates a faulty coil pack and leads to misfiring, which often causes poor engine performance. The signs of a faulty coil pack are similar to those of a defective spark plug. These signs include an apparent lack of power, an unusually noisy engine, a rough idle, a blinking check engine light and an unexpected acceleration accompanied by a considerable decrease in revolutions per minute. Other indications of a coil pack problem include an active gas warning light despite having lots of gasoline and an intermittent emission of smoke from the exhaust.
A vehicle engine needs to burn plenty of fuel in the cylinder to produce a high voltage supply for creating a spark at the spark plug. The coil pack is responsible for accumulating up to 75,000 volts of energy once the combustion process starts. The coil pack delivers the voltage to the spark plug through the spark plug cables when the vehicle?s electronic control module signals the ignition control. The spark travels to the ground from the spark plug gap and goes to the spark plug.