* Misfires: This is the most common symptom. Your engine will run roughly, possibly sputtering or hesitating, especially at higher RPMs. You might also notice a decrease in fuel economy. A diagnostic trouble code (DTC) from an OBD-II scanner will often pinpoint a specific misfire cylinder, helping identify the faulty coil pack.
* Engine stalling: In severe cases, a failing coil pack can cause the engine to stall completely.
* Difficulty starting: A malfunctioning coil pack can make it harder to start the engine.
* Visible damage: Inspect the coil pack visually for cracks, burns, or corrosion. While not always indicative of immediate failure, damage suggests potential problems.
* Age: While not a guaranteed indicator, very old coil packs are more prone to failure. If your vehicle is significantly older, preventative replacement might be considered, especially if other components are showing age.
It's important to note that a misfire can be caused by other issues besides a bad coil pack, such as spark plugs, wires, or fuel injectors. A mechanic using a diagnostic scanner can properly diagnose the problem. Don't just replace coil packs randomly; get a proper diagnosis first.
