Which of the following could indicate an issue with the ignition system?

An issue with the ignition system can manifest in various ways, directly impacting the engine's performance. When a vehicle has difficulty starting, this can suggest that the ignition system is not delivering a strong enough spark to ignite the air-fuel mixture in the cylinders, which is essential for starting the engine. Similarly, if the engine is stalling, it may indicate that the ignition system is failing to maintain a consistent spark, resulting in intermittent engine power and causing it to shut down suddenly.

Additionally, excessive fuel consumption can be a symptom of problems within the ignition system. If the ignition system is not providing a proper spark at the right time, it can prevent the air-fuel mixture from combusting efficiently. This can lead to incomplete combustion, which forces the engine to use more fuel than necessary to operate, thus increasing fuel consumption.

Given that all of these symptoms can be linked to potential ignition system issues, the correct answer encompasses all these possibilities, indicating the broad impact a malfunctioning ignition system can have on vehicle operation.