How do you know if coil pack is ok?

To determine if a coil pack is functioning properly, you can perform a few checks. First, inspect for any visible damage, such as cracks or corrosion. Then, use a multimeter to measure the resistance; a typical reading should fall within the manufacturer's specified range. Additionally, if the engine is misfiring or experiencing poor acceleration, it may indicate a faulty coil pack, which can be confirmed through diagnostic trouble codes from an OBD-II scanner.