Obvious Signs:
* Engine won't start: This is the most obvious sign. If you turn the key and hear nothing, or only a weak clicking sound, the fuel pump might be the culprit. (However, this could also be the starter motor or battery.)
* Engine stalls frequently: Especially when accelerating or under load. The pump can't keep up with the fuel demand.
* Engine sputters or hesitates: Similar to stalling, this suggests an inconsistent fuel supply.
* Loud humming or whining noise from the fuel tank: This is a clear indication of a failing fuel pump. It's usually a higher-pitched, continuous sound.
Less Obvious Signs (requiring more investigation):
* Reduced fuel economy: A weak pump may not deliver fuel efficiently, leading to lower MPG.
* Difficulty starting when the tank is low: The pump has to work harder to draw fuel from the bottom of the tank.
* Engine runs rough, especially at higher RPM: The engine struggles to get enough fuel.
* Check engine light is on: This light illuminates when the car's computer detects a problem, and a fuel pump issue can trigger it. You'll need a diagnostic scan to pinpoint the problem. (The code might not *directly* say "fuel pump," but it could indicate low fuel pressure.)
Important Considerations:
* Don't confuse a clogged fuel filter with a bad fuel pump. A clogged filter restricts fuel flow and can cause similar symptoms. Replacing the fuel filter is a cheaper and easier fix than replacing the pump.
* Listen for the fuel pump's prime: Many cars have a fuel pump that primes (runs briefly) when the ignition is turned on but before the engine is cranked. If you don't hear this, the pump may be faulty or not receiving power.
* Fuel pressure test: A mechanic can perform a fuel pressure test to definitively determine if the pump is delivering the correct pressure. This is the most accurate way to diagnose a failing fuel pump.
If you suspect your fuel pump is failing, it's best to take your vehicle to a qualified mechanic for diagnosis and repair. Attempting to replace the fuel pump yourself can be dangerous due to fuel system pressure and potential fire hazards.
