What Are the Symptoms of a Bad Fuel Pump?

A failing fuel pump affects how your car starts, idles, and accelerates.
Here’s what to watch out for:

1. Whining or Sputtering Sounds

A high-pitched whining from the fuel tank or a sputtering engine can point to a failing fuel pump. If the sound is accompanied by backfires or a rough idle, the pump may not be maintaining consistent fuel pressure.

NOTE: Sound-related issues may trigger the Check Engine Light.

2. Difficulty Starting

If the fuel pump can’t supply enough fuel, your engine may take longer to start or need multiple attempts. Left unchecked, the car might eventually refuse to start at all.

3. Engine Hesitation, Surging, or Loss of Power

An erratic or weak fuel supply can cause the engine to surge, hesitate, or lose power — especially under load, during acceleration, or at high speeds. This may feel like you’re running out of gas even when your tank is full. A sputtering engine on the highway is a classic warning sign.

4. Misfiring and Rough Idle

A malfunctioning fuel pump may prevent the engine from receiving enough fuel, throwing off the air-fuel ratio. This inconsistent fuel supply can lead to misfires, rough idle, and, over time, a noticeable reduction in fuel economy.

5. Overheating and Stalling

A worn or weak fuel pump can overheat, especially with extended use. Your vehicle may run fine for 15-30 minutes, then suddenly stall. Once the pump cools down, you can restart the engine — only for the cycle to repeat.

6. Low Fuel Pressure

If you suspect a pump issue, check the fuel pressure with a gauge. Low readings may mean the fuel pump, its gasket sealer, or the pressure regulator is failing. 

TIP: Refer to your owner’s manual for the correct fuel pressure specification.

Is it Safe to Drive with a Bad Fuel Pump?

It’s generally not safe to drive with a failing fuel pump. A weak fuel supply can cause your engine to stall without warning — which is dangerous in traffic, especially if you drive a truck or larger vehicle. 

You might also experience hesitation, surging, or sudden power loss, making your vehicle unpredictable to handle. Continuing to drive can also damage other parts, such as the catalytic converter. Have the pump checked and replaced as soon as possible with a new fuel pump.

How Much Does it Cost to Replace a Fuel Pump?

Prices may vary year-to-year, but the total cost of replacing a fuel pump typically ranges between $1,100-$1,300:

• Part costs: $500 to $600
• Labor costs: $600 to $700

The amount may increase if other components need replacement. Here are estimated prices for some related parts (not including labor):

• Fuel filter: $90-$110
• Fuel pump relay: ~$45
• Fuel tank pressure sensor: $125-$200

How to Perform a Fuel Pump Replacement

If your car shows signs like hard starting or engine misfiring, a fuel pump replacement may be needed to restore proper fuel delivery and performance.

IMPORTANT: You can replace the fuel pump yourself, but because this job involves working with gasoline, which is highly flammable, it’s best left to a qualified mechanic. If you choose to DIY it, wear safety gear, work in a well-ventilated area, and keep emergency tools on hand.

Step-by-step overview:

1. Confirm the issue: Check fuel pressure using a gauge and inspect the fuel pump fuse and relay. If pressure is low and the electrical system checks out, the pump is likely failing.
2. Prepare the vehicle: Park on a level surface, engage the parking brake, relieve the fuel system pressure (via the Schrader valve or fuel pump fuse), and disconnect the negative battery cable.
3. Drain and lower the fuel tank: Safely drain as much fuel as possible. Disconnect the filler hose, vent lines, and electrical connectors. Support the tank with a jack and a block of wood, then remove the mounting straps and lower the tank carefully.
4. Remove the old pump: Disconnect the fuel lines and remove the retaining ring or bolts holding the pump assembly. Take out the old pump and sending unit, and clean the tank opening to prevent debris from entering.
5. Install the new pump: Compare the new pump with the old one to ensure a correct match. Install it with a new gasket or O-ring, reconnect the fuel lines, and secure the assembly.
6. Reinstall and test: Raise the tank back into place, reconnect the hoses and electrical connectors, and reinstall the straps. Reconnect the battery, add fuel, and turn the key to the “ON” position (without starting) to prime the pump. Then start the engine and check for leaks or irregular pressure.

TIP: Always replace the fuel filter when installing a new fuel pump to prevent early failure.

3 FAQs About the Fuel Pump

1. What Is a Fuel Pump? 

A fuel pump is a critical part of your vehicle’s fuel delivery system. Its job is to move fuel from the tank to the engine — either to the carburetor in older vehicles or the fuel injectors in modern ones. This steady flow keeps the engine running smoothly.

2. How to Make the Fuel Pump Last Longer?

You can extend your fuel pump’s lifespan with a few simple habits:

• Keep your tank at least a quarter full. Driving frequently on low fuel can cause the pump to overheat and accelerate wear.

• Use clean, quality fuel. Contaminated gasoline can damage the pump and clog the fuel filter.

• Keep the tank area clean. Dirt or debris around the fuel filler or pump assembly can enter the system and block fuel flow.

Even with good maintenance, a fuel pump may begin to show signs of failure after 7-8 years or 100,000 miles.

3. Can You Rebuild or Repair a Fuel Pump?

Usually, no. 

Modern fuel pumps are sealed electric units, so their internal parts can’t be serviced. Once they fail, the entire pump assembly must be replaced. Attempting a repair has more cons than benefits, so for most car or truck owners, replacement is safer and simpler.