Signs of a Bad Coil Pack

A coil pack is an automobile component that works to help the fuel ignite in the cylinders by giving the spark plugs a high voltage of electricity. This automobile component is located under the hood and can be found on most vehicles by following the spark plug wires. When a coil pack is faulty, certain signs and symptoms will be present.

Power Symptoms

  • Several signs of a bad coil pack are present when driving the vehicle. The vehicle may have a rough idle, an unexplainable and abnormally louder engine and a noticeable reduction in power.

Accelerating Symptoms

  • A major drop in RPM's during acceleration can occur. This can be determined by watching the RPM gauge while driving. During acceleration the check engine light either comes in intermittently or blinks.

Other Symptoms

  • When the vehicle is running the exhaust smoke comes out intermittently instead of in a normal steady stream. When the vehicle has plenty of fuel the gas warming light goes on intermittently.