When diagnosing engine hesitation, which system should be inspected first?

In the context of diagnosing engine hesitation, the fuel delivery system is often the most critical area to inspect first. This system is responsible for supplying the necessary fuel to the engine for combustion. If there are issues such as inadequate fuel pressure, clogged fuel filters, malfunctioning fuel injectors, or a failing fuel pump, the engine may struggle to receive the proper amount of fuel. This lack of fuel can lead to hesitation during acceleration or when the engine is under load.

Conversely, while the ignition system is also essential for engine performance—ensuring the spark plugs fire correctly and at the right time—fuel-related problems tend to manifest more readily as hesitation symptoms. If the fuel delivery system is functioning correctly, the next logical step would be to inspect the ignition system if hesitation persists. Other systems like the exhaust system and transmission system are less likely to cause direct hesitation issues compared to fuel delivery. Therefore, beginning diagnostics with the fuel delivery system makes sense based on its direct impact on engine performance.