A larger spark plug gap will cause which of the following?

A larger spark plug gap can indeed result in both misfires and secondary ignition damage. When the gap is wider than specified, the spark may not be able to adequately jump the gap under high cylinder pressure and temperature conditions. This can lead to incomplete combustion, which manifests as engine misfires.

Additionally, if the ignition system is required to produce a stronger spark to jump the larger gap, it can put extra stress on components like the ignition coil and other ignition system parts. Over time, this increased demand can lead to secondary ignition damage, resulting in failure of components and decreased performance.

Thus, the correct answer reflects both possible outcomes from having a larger spark plug gap: it can lead to misfires due to inadequate sparking and can cause damage to the ignition system from the additional strain required to maintain effective operation.