* Engine cranks but won't start: This is a classic symptom. The engine turns over, indicating the starter is working, but there's no fuel to ignite.
* Hesitation or sputtering during acceleration: The engine struggles to maintain power, especially under load. This is due to an inconsistent fuel supply.
* Loss of power: Similar to sputtering, but more severe. The engine may lose power completely, especially at higher speeds or when climbing hills.
* Engine stalling: The engine suddenly cuts out while driving or idling.
* Surging or erratic idle: The engine speed fluctuates unevenly.
* Weak fuel pressure: This requires a professional mechanic to measure with a fuel pressure gauge. Low pressure directly indicates a faulty pump.
* Whining noise from the fuel tank: You might hear a whirring or buzzing sound coming from the fuel tank area, especially when the ignition is turned on. This is the pump trying to operate but failing. This noise may only be present briefly before the engine dies.
* Reduced fuel economy: Although not always indicative of a *faulty* fuel pump, a significant drop in MPG could be a symptom of a *weakening* pump that isn't delivering optimal fuel flow.
Important Note: Many of these symptoms can also be caused by other issues, such as a clogged fuel filter, faulty fuel injectors, problems with the ignition system, or a bad mass airflow sensor. A proper diagnosis by a qualified mechanic is essential to determine the actual cause. Don't jump to conclusions and replace the fuel pump without a thorough inspection.
