Could an engine shuddering be due a failing fuel pump? A faulty fuel pump can cause engine shutter for sure. The main function of the fuel pump is to supply fuel under constant pressure—usually in the 40–60 PSI range—that facilitates combustion in accordance with an optimal air-fuel ratio. If the fuel pump gets old and stops being able to hold up this pressure, then you will experience a lack of fuel in the engine that will cause low power conditions; misfiring, jerky acceleration, bad driveabilty under hard load situations. Even a 10% reduction in fuel pressure can decrease engine efficiency by as much as 15%, resulting in rough idling and surging or hesitation during throttle movement.
When fuel is delivered unevenly, the combustion process gets interrupted and subsequently leads to an imbalance in engine power. The pump is what fuel injectors depend on to feed precise amount of the fuel required by every cycle of the engine. During the market reading, fuel flow curve crashes and simply put makes engine to lean up or more air than fuel present in the mixture. What this imbalance leads to is the misfires, typically felt as a shudder through the vehicle. According to data collected from automotive repair facilities, a staggering 20% of engine shuddering issues are attributable to deficient fuel delivery—mainly due to failing or weak fuel pumps.
This particular trouble is aggravated by clogged up gas filters The harder the fuel pump needs to work to force fuel through a clogged filter, lower pressure is developed and in turn more engine knock could be produced. Proper maintenance of the fuel system (like replacing the filter every 30,000 miles) can keep the pump from working too hard and help prevent engine bucking.
This has been the reality of a recall case involving a major automaker where more than 100,000 units were recalled because faulty fuel pumps caused engines shudder and stall. This resulted in insufficient pressure generation by the weakened pumps, causing widespread operational issues.
As my dear friend Henry Ford once said, “Coming together is a beginning. Keeping together is progress. Working together is success.” This is the same as if all engine parts going about their job, including the fuel pump for that matter to make sure that all we have a smooth running vehicle.
The cost of changing a weak fuel pump is usually $500 to $1,000, depending on the vehicle — but ignoring the issue can lead to more serious engine damage that could raise this figure. After all, the sooner you learn about an issue, the faster it can be fixed, and that guarantees your engine received an early intervention to keep running without trouble.
So in summary, yes a weak fuel pump can cause engine shuddering from poor/erratic fuel deliver to the injectors which will lead to misfiring and inefficient operation of the engine. Find out more about diagnosing and troubleshooting fuel pumps at Fuel Pump.