Nissan Technical Advisor 7/15/2011Could be worn out plugs or defective ignition coil. Weak spark and ignition coil not firing are two of the most common ignition coil problems you are likely to face with your vehicle. At times, the ignition coil is totally worn out and doesn't produce any spark at all. But there are times wherein excessive wear and tear affects the coil, and results in weak sparks, which in turn reflect on the performance of the vehicle. Though ignition coils are made from silicon-iron alloy, and have a strong capacity to tolerate heat, other components of the ignition system are not. These components get overheated pretty soon, and the rise in temperature within the system tends to hamper the ability of the ignition coil to conduct electricity, thus resulting in ignition system failure.