A faulty fuel pump results in jerky movements of the engine because it can’t keep up with a constant fuel supply to the engine. Fuel pumps are designed to supply fuel at a certain pressure, normally in the range of 40 to 70 psi for most vehicles, ensuring smooth combustion. A failing fuel pump often struggles to provide the required fuel pressure to the engine, leading to intermittent fuel supply. This will cause an engine to have irregular power delivery, which can lead to jerky or stuttering movements.
For instance, a 2019 study by the Automotive Service Association showed that 18% of stalling and jerking engine symptoms were traced back to a faulty fuel pump supplying inconsistent fuel. When fuel pressure becomes fluctuating, the air-fuel mixture required for combustion becomes erratic. This inconsistency in the supply of fuel results in hesitation or jerking when the engine is under load, especially on acceleration or deceleration. As a fact, a malfunctioning pump is among the top five causes of engine hesitation reported by vehicle owners in the 2020 AAA vehicle survey.
Symptoms of jerky movements are usually more pronounced on high-mileage vehicles or those that have been operated in extreme temperatures. Over 100,000 miles, the fuel pump naturally loses efficiency and thus delivers fuel less precisely. As per the 2021 report by AutoCare, almost 12% of fuel pump failures in older vehicles result in unstable fuel flow, leading to jerky movements or misfires. This is especially true in situations where the engine demands a consistent fuel supply, such as city driving or during acceleration after a stop.
Besides that, internal parts of the fuel pump, like the fuel filter or fuel injectors, may become clogged over time. This results in partial blockage, restricting the fuel flow to the engine. A clogged fuel filter can decrease fuel flow by up to 50%, making it difficult for the engine to get enough fuel, causing it to stumble or jerk, particularly under load.
“Jerky movements are often the first sign that something is wrong with the fuel delivery system,” says car mechanic Jennifer Martin. “When the fuel pump can’t maintain the proper pressure, it leads to fuel starvation, which directly affects the engine’s performance and causes that jerky feeling.”
This fuel delivery problem can also be progressive in nature. The jerking may become more frequent and intense as the fuel pump continues to deteriorate, hence affecting fuel consumption and the overall performance of the engine. A faulty fuel pump can also put undue strain on other parts of the engine, such as the fuel injectors and the engine control unit (ECU), which may also start to show signs of malfunction.
Replacing a faulty fuel pump not only resolves jerky engine movements but also restores fuel efficiency and prevents further engine damage. The typical cost of replacing a fuel pump ranges from $400 to $600, but it can save drivers from costly repairs related to more extensive engine damage. For high-quality replacement parts that ensure smooth engine operation, visit Fuel Pump, where top-rated products guarantee consistent fuel delivery and improved engine performance.