What are the symptoms of a fuel pump going bad?

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A fuel pump typically doesn't abruptly stop functioning. In most cases of fuel pump failure, the failure is preceded by numerous symptoms of a fuel pump going bad.

Taking the time to become familiar with these symptoms can help keep you from becoming stranded at an inconvenient time and place, as the problem can be confirmed and dealt with before the fuel pump fails completely.

Power Loss

Because it is typical for a failing fuel pump to have intermittent mini-failures before it reaches the point of complete and total failure, watch for distinct instances of power loss that occur with increasing frequency. This loss of power can be experienced when starting from a stopped position or when moving at the higher speeds associated with highway driving. This loss of power is sudden, with the return of engine power being equally as sudden, as the pump stops functioning fully and then abruptly returns to normal function.


Another common symptom is a delayed response to fuel demand. When the driver presses the fuel pedal sharply, such as when passing another vehicle, there is a distinct hesitation in vehicle response, which could indicate that the fuel pump is not functioning well enough to respond to the increased fuel demand as quickly or smoothly as it should.


As the condition of the fuel pump continues to deteriorate, what was once hesitation could become stalling. This is more common when making a fuel demand from a stopped position, but stalling at higher speeds is not unheard of. If the fuel pump is not moving the fuel smoothly or is doing so intermittently, the engine may not get enough to continue operating, resulting in stalling.

Difficulty In Starting Vehicle

When a fuel pump is in the process of going bad, starting the vehicle may be difficult at times. That is because the engine cannot start without the correct flow of fuel. A fuel pump that has not yet reached full-out failure and is intermittently functioning or is slow to respond to fuel demand may require multiple attempts at starting the vehicle before successfully providing the necessary fuel flow. If experiencing difficulty in starting along with other symptoms of a fuel pump going bad, odds are that time is growing short for the fuel pump and complete failure is imminent. Take heed and act soon to avoid being stranded.