A faulty fuel pump is one of the nastiest ways to break down for any vehicle. Sign 1: Engine Slows Down On Acceleration One of the earliest symptoms that a fuel pump is going bad, is a reduction in power under acceleration. A 10% reduction in fuel flow can significantly reduce performance, especially under high load conditions such as climbing hills or passing on the highway. When the pump is unable to deliver sufficient pressure (somewhere in the 40-80 psi range for most fuel-injection systems) it causes fuel starvation, which results in an engine stall and backfire.
Fuel starvation is the name of this-- in fact, that is why any engine starts rough: some cylinders are very lean; real shit cannot burn. This will most likely happen when the fuel pump itself cannot deliver the proper volume of fuel to the injectors. This can result in expensive engine repair if left unattended. Engine replacement as a result of fuel starvation could be in the $4,000 and up range, while a fuel pump replacement costs between $300 to $900 — depending on make and model. Given the initial cost of pump replacement, any additional expense would need to be justified and not exceed the benefit.
In motorsports, a failure of the fuel pump can be catastrophic — in circumstances when only seconds matter an instant drop in fuel pressure guaranteed victory lost. That led to a leading car dropping out of the 2016 Daytona 500 because of an issue with the fuel system that otherwise could have been avoided, which in turn proved costly for Haas, losing millions in potential prize money and sponsorships. Its a high stakes version of what can go wrong when the fuel pump stops working properly.
According to the legendary racing driver, Ayrton Senna once said of reliability: "Second is only the first loser.". A bad fuel pump in performance tailored cars will not only hamper the high revs but also has a chance of causing sudden power outage. Drivers typically refer to this feeling as the car jerking or choking, under load as it happens when the engine does not receive enough fuel to match what comes in through the air intake -- leading to an incorrect air-fuel mixture.
If the fuel pump is going bad, another common symptom would be engine misfires. Misfires are when one digit (on the flip side of a head quarter) is not firing the right amount of fuel, causing it to happen improperly in a state that already has its own interruption from there. With repetition, however, constant misfires can ruin the catalytic converter, a repair that could be $ 1,000 or more; The average lifespan of a fuel pump is somewhere between 100,000 and 150,000 miles; however, that life expectancy can be shortened by contaminated fuel or even just a restricted fuel filter leading to premature failure.
The “What happens if I avoid a failing fuel pump? the answer is clear. Failing to heed the warnings may result in your engine shutting down entirely, making you a sitting duck that will necessitate towing (which can cost around $75 to $125). What is more, a sudden loss of power can lead to accidents in critical situations such as heavy traffic or harsh weather. It is also a simple fix for making sure you are not going to have further problems later than simply changing out your fuel pump.
Read this Fuel Pump Resource for more info on choosing the correct fuel pump for your ride.