A faulty fuel pump can indeed cause engine misfires at high speed due to disruption in the orderly function of fuel delivery to the engines. Fuel pumps are therefore crucial to ensure that fuel in the tank flows to the engine at a certain pressure usually in the region of about 40 to 60 psi in modern vehicles. Whenever a fuel pump starts to fail due to clogging, wear, or electrical issues, the supply of fuel becomes inconsistent, especially at higher speeds where the engine demands more fuel for combustion.
In a study conducted by the Car Care Council in 2020, almost 12% of all vehicle breakdowns were attributed to failures in the fuel system, and among the top causes were problems with the fuel pump. At highway speeds, usually about 60 to 70 mph, the engine needs a constant and strong flow of fuel for smooth operation. If the fuel pump is compromised, it cannot deliver fuel at the required pressure, leading to irregular fuel flow. This interruption can cause the engine to misfire, hesitate, or even stall in some cases.
In this regard, many car owners have complained of misfires after the vehicle reaches a certain speed. This occurs because the engine has to labor more when at higher speeds, and any inconsistency in the fuel supply becomes magnified. If the fuel pump is unable to provide the required quantity of fuel, then the air-fuel mixture within the combustion chamber becomes too lean due to a greater amount of air compared to fuel, causing the engine to misfire. In extreme cases, this might cause the engine to stall, especially if it is already under load, such as going uphill or accelerating quickly.
The symptoms of a clogged or failing fuel pump generally worsen with an increase in the power demand of the engine. A driver might notice that the engine stutters or hesitates at higher speeds when accelerating or the vehicle stutters when trying to maintain a consistent speed. Research by the National Institute for Automotive Service Excellence indicates that this type of problem is normally due to a gradually deteriorating pump, whereby the loss of its pressure-sustaining capability has worsened over time to the extent that it can no longer meet the demands made upon it by the engine.
For example, in the case of a 2017 Honda Civic, owners reported that their car would misfire after driving for an extended period on the highway. The problem was found to be with a worn-out fuel pump that could not maintain the required pressure at high speeds, leading to sputtering and misfires while accelerating. In such a case, replacement of the fuel pump restored normal operation, eliminating the misfire issue at high speeds.
In conclusion, a failing Fuel Pump can significantly impact engine performance, particularly at high speeds where the engine requires a constant and steady fuel supply. Inconsistent fuel flow caused by a clogged or worn-out pump can result in misfires, hesitation, and potentially even engine stalling, especially under high demand. Regular maintenance will go a long way in ensuring that such problems do not arise, especially for those that have crossed the 100,000-mile mark where the wear and tear of fuel pumps are common, along with clogging.