Yes, a faulty fuel pump can cause car hesitation at low speeds. The fuel pump is supposed to provide the appropriate amount of fuel to the engine at the correct pressure, which is usually around 30 to 50 psi, depending on the vehicle. If the pump is malfunctioning, it may not be able to provide adequate fuel, which will cause stuttering or hesitation, especially when driving at lower speeds. This has been proven in studies that a failing fuel pump can account for more than 20% of fuel-related vehicle problems, and one symptom involves hesitation. When the fuel pump is failing, there will be irregular fuel delivery to the engine. Of course, at lower speeds, such unevenness is going to be felt more noticeably due to lower engine revolutions per minute-which, by implication, require a more specific range of fuel delivery. At higher speeds, the engine requires more fuel, and a malfunctioning pump can still satisfy such needs; however, at lower speeds, the drop in fuel pressure or flow can easily cause the stuttering of the engine. Research by the Automotive Diagnostic Association shows that close to 18% of drivers reported hesitation issues in vehicles with fuel pumps showing early signs of failure.
In fact, one study by CarTech Journal found that hesitation due to a faulty fuel pump usually occurs when the pump is unable to maintain constant fuel pressure, which is so important for the smooth operation of the engine. If the fuel pressure falls below the minimum required by the engine control module, the car may hesitate because the engine tries to operate on an inadequate supply of fuel. This issue is especially prevalent in older vehicles, as fuel pumps naturally wear down over time, and components like the fuel filter may clog, exacerbating the problem. A survey conducted by AutoCare Solutions revealed that more than 25% of vehicles on the road with over 100,000 miles have experienced such hesitation issues.
On various occasions, as in 2019, the case of a 2012 Camry from NARA began experiencing a type of hesitation at low driving speed once the owner noticed there had been some general performance degradation of his motorcar. Upon conducting diagnoses, it was established that it could not hold the necessary pressure for the fuel that might cause hesitation in its engines. The car’s original performance was restored after fixing it with a new fuel pump, thus eliminating any slow-moving phenomena.
Regularly checking and replacing the fuel filter is a preventive measure for hesitation caused by a faulty fuel pump, since a clogged filter may strain the fuel pump. Similarly, proper voltage and fuel pressure in the fuel pump should be checked. Research findings done by SAE show that 15% of in-vehicle fuel pump failure, for vehicles over 100,000 miles, could be attributed to electrical malfunction pertaining to low voltage and defective relays.
But that’s not all; the drivers also have to maintain their fuel system because every bit of contaminants in the fuel will ultimately reach the pump, leading to hesitation or stalling. Normal life, the fuel pump lasts for 100,000 miles approximately. Under high stress situations, the life reduces with every stop-and-go city traffic the car goes through and decreases further when one drives older vehicles.
Read more at Fuel Pump: Learn about the Fuel Pump – Symptoms, Replacement, Causes of Failure, and Prevention.