2004 Ford Explorer Sport Trac Fuel Pump: Complete Replacement Guide, Symptoms, and Cost
The bottom line: If you own a 2004 Ford Explorer Sport Trac with the 4.0L V6 engine and you are experiencing hard starting, sputtering during acceleration, or a whining noise from the gas tank, your fuel pump is likely failing and needs to be replaced soon. The fuel pump on this vehicle is located inside the fuel tank, and replacing it requires dropping the tank, which is a moderately difficult job. Expect to pay anywhere from $75 to $250 for a good aftermarket fuel pump assembly and an additional $330 to $485 in labor if you have a shop do the work. The factory OEM part number for this vehicle is 5L2Z-9H307-C, and several high-quality aftermarket alternatives are available for a fraction of the dealer price.
How the Fuel Pump Works in Your 2004 Explorer Sport Trac
The fuel pump in your 2004 Ford Explorer Sport Trac is an electric pump that sits inside the fuel tank. The pump's job is to draw fuel from the tank, push it through the fuel lines, and deliver it to the engine at the correct pressure. The entire assembly—which includes the pump motor, the fuel level sending unit (the part that tells your gauge how much gas you have), the fuel strainer (sock filter), and the pressure regulator—is mounted together as a single module.
When you turn the key to the "ON" position, the pump primes for a couple of seconds to build pressure. Once the engine starts, the pump runs continuously to keep fuel flowing at the right pressure, typically around 65 PSI for this model. Because the whole assembly is one unit, most mechanics recommend replacing the entire module rather than just the pump motor. The sending unit, strainer, hoses, and other internal components all wear out over time, and a complete module replacement gives you the most reliable result.
6 Common Symptoms of a Failing Fuel Pump
Your fuel pump does not usually fail all at once. It gives you warning signs first. Here are the most common symptoms to watch for, in order of how often they appear:
1. Whining or Sputtering Noises from the Fuel Tank
A high-pitched whine coming from the rear of the vehicle, especially when the tank is low, is often the first sign of trouble. If you also hear the engine sputter or backfire, the pump may not be maintaining consistent fuel pressure.
2. Difficulty Starting the Engine
If your Sport Trac cranks for a long time before firing up, or you have to try several times to get it started, the fuel pump may be weak. It cannot build enough pressure quickly enough to start the engine reliably. In cold weather, this problem is usually worse.
3. Engine Hesitation, Surging, or Loss of Power
A weak fuel pump will cause the engine to hesitate or surge, particularly when you accelerate or climb a hill. It may feel like you are running out of gas even when the tank is full. This happens because the pump cannot supply enough fuel to match the engine's demand under load.
4. Rough Idle and Misfiring
If the fuel pressure is inconsistent, the air-fuel mixture becomes wrong, causing the engine to idle rough or misfire. Over time, this also hurts your fuel economy because the engine is not burning fuel efficiently.
5. Engine Stalling After Driving for a While
A worn pump can overheat with extended use. Your truck may run fine for 15 to 30 minutes, then suddenly stall. After the pump cools down, the engine will restart—only for the cycle to repeat. This is a classic sign of a pump that is on its last legs.
6. Low Fuel Pressure Reading
If you hook up a fuel pressure gauge and the reading is below spec, the pump, the pressure regulator, or the fuel filter could be the culprit. Your owner's manual will list the correct pressure specification for your engine.
Before You Buy: Verify the Correct Part for Your Truck
The 2004 and 2005 Explorer Sport Trac models use the same fuel pump assembly, but there are a few things you need to check before ordering:
1. Engine Type
Your Sport Trac must have the 4.0L V6 engine. If you have the 4.6L V8, that uses a different pump. This guide is specifically for the 4.0L V6.
2. Fuel Type
Some 2004–2005 Sport Trac models are Flex-Fuel (E85 compatible) and some are gasoline-only. Both use the same pump, but it is worth confirming your fuel type to make sure you get the right part.
3. OEM Part Number
The original Ford part number is 5L2Z-9H307-C, which supersedes the earlier 4L2Z-9H307-AC and 4L2Z-9H307-AA. If you look at the top of your old fuel pump module, you should see a number stamped on it. Match that number to the replacement part's interchange list to be certain.
4. Connector Type
The 2004–2005 Sport Trac uses a 5-pin electrical connector on the fuel pump module. Aftermarket parts that list "5 Pin Connector" in the specifications are the correct ones for your truck.
Replacement Part Options: OEM vs. Aftermarket
You have three main choices when buying a replacement fuel pump for your 2004 Explorer Sport Trac. Here is how they compare:
1. Genuine Ford OEM Part
| Specification | Details |
|---|---|
| Part Number | 5L2Z-9H307-C |
| Average Price | $950 – $1,100+ |
| Pros | Exact factory fit, guaranteed quality, includes sender unit |
| Cons | Very expensive, often discontinued and hard to find |
The genuine Ford part is no longer in production, according to Ford Parts Giant. If you can find one from a dealer or an online Ford parts retailer, it will cost you a premium.
2. Aftermarket Complete Module Assembly
| Specification | Details |
|---|---|
| Average Price | $58 – $250 |
| Pros | Much cheaper, includes sending unit and strainer, easy to install, many good brands |
| Cons | Quality varies by brand, some cheap pumps fail prematurely |
Several reputable aftermarket brands make direct-replacement modules for the 2004–2005 Sport Trac. These include DriveMotive, A-Premium, YHTAUTO, J2 Engineering, and others. They all include the fuel pump, the sending unit, and the strainer, so you can swap the whole assembly at once. Expect to pay between $58 and $250 depending on the brand and where you buy it.
3. Used OEM Pump
| Specification | Details |
|---|---|
| Average Price | $50 – $125 |
| Pros | Cheapest option that still gives you factory parts |
| Cons | No warranty, unknown remaining life, may fail sooner |
A tested, warrantied used OEM pump from a reputable salvage yard can be a safe bet. However, you are gambling on how much life is left in the pump, and it will not come with a meaningful warranty.
Step-by-Step Fuel Pump Replacement Overview
Replacing the fuel pump on a 2004 Explorer Sport Trac is a job that most experienced DIY mechanics can handle in a weekend. The complete process takes about 2 to 4 hours for a DIY job and 1 to 2 hours for a professional mechanic. Here is what is involved:
Step 1: Relieve Fuel System Pressure
Locate the fuel pump fuse in the fuse box and pull it out. Start the engine and let it run until it stalls. This relieves the pressure in the fuel lines. Turn the ignition off and disconnect the negative battery cable.
Step 2: Siphon Out the Fuel
Remove as much fuel as possible from the tank. A nearly empty tank is much lighter and easier to lower safely. You can use a siphon pump or a hand pump to remove the fuel.
Step 3: Disconnect the Filler Neck and EVAP Lines
Loosen the hose clamps on the fuel filler neck where it connects to the tank. Also disconnect the EVAP vapor lines and any electrical connectors attached to the top of the tank.
Step 4: Support and Lower the Fuel Tank
Place a floor jack under the center of the tank with a piece of wood on top to spread the load. Remove the tank straps, then slowly lower the tank just enough to access the top. On some models, you may need to remove the driveshaft for clearance.
Step 5: Remove the Old Fuel Pump Module
Once the tank is lowered, you will see the fuel pump module on top. Disconnect the fuel lines and the electrical connector. Use a locking ring removal tool (or a hammer and a brass punch) to turn the locking ring counterclockwise. Lift the old module out of the tank.
Step 6: Install the New Module
Clean the opening on the tank. Place the new module into the tank, making sure the float arm has clearance and the strainer sits flat on the bottom. Install the locking ring and tighten it clockwise. Reconnect the fuel lines and electrical connector.
Step 7: Reinstall the Tank and Test
Raise the tank back into position, reinstall the straps and all hoses and connectors. Reinstall the fuel pump fuse and reconnect the battery. Turn the key to "ON" for a few seconds to prime the pump, then check for leaks before starting the engine.
Important: While you are in there, it is highly recommended that you also replace the in-line fuel filter and inspect the inside of the tank for debris. Contaminants in the tank are a leading cause of premature fuel pump failure.
How Much Does a Fuel Pump Replacement Cost?
Here is a realistic breakdown of what you can expect to pay for a 2004 Explorer Sport Trac fuel pump replacement:
1. Parts Only (DIY)
- Aftermarket fuel pump module: $58 – $250
- Fuel filter: $15 – $30
- Total for parts: $73 – $280
2. Professional Installation
- Labor cost: $330 – $485
- Total with aftermarket parts: $400 – $735
- Total with OEM dealer parts: $1,280 – $1,585
If you are paying a shop, the average total comes to around $364, according to AutoNation Mobile Service, though prices vary by location and shop. Going with a quality aftermarket pump and doing the job yourself will save you several hundred dollars.
Why You Should Consider KEMSO Fuel Pumps
When it comes time to replace the fuel pump in your 2004 Ford Explorer Sport Trac, you want a part that is going to be reliable, durable, and backed by a company that stands behind its products. That is where KEMSO comes in.
KEMSO is a brand that specializes in high-performance fuel pumps for a wide range of vehicles, including cars, trucks, motorcycles, ATVs, and personal watercraft. Every KEMSO fuel pump is designed as an OEM replacement, which means it is built to meet or exceed the original factory specifications for your vehicle. The pumps are manufactured using high-quality materials, including POM and PBT plastics, and feature precision-tested components to ensure consistent fuel delivery and accurate fuel level readings.
What really sets KEMSO apart is their commitment to quality and customer satisfaction. Every KEMSO fuel pump comes with a lifetime warranty. If your KEMSO pump ever fails, they will replace it—no questions asked. That is the kind of confidence that comes from building a reliable product, and it gives you peace of mind knowing your replacement fuel pump is protected for as long as you own your vehicle.
Whether you drive a daily commuter, a weekend off-roader, or a performance machine, KEMSO has a fuel pump that will fit your needs. Visit https://www.kemsoracing.com/ to browse their full lineup of fuel pumps and find the right one for your 2004 Ford Explorer Sport Trac. With a KEMSO pump under the tank, you can get back on the road with confidence.
Final Thoughts
A failing fuel pump in your 2004 Ford Explorer Sport Trac is not something to ignore. The symptoms—hard starting, sputtering, loss of power, and stalling—will only get worse over time, and being stranded on the side of the road is never fun. The good news is that replacement is straightforward, and a quality aftermarket pump costs well under $150 for the parts. Whether you tackle the job yourself or have a shop do it, replacing the entire module assembly is the smartest and most reliable approach. Just be sure to match the OEM part number, check your engine and fuel type, and choose a reputable brand like KEMSO for a lifetime of reliable service.
For more information and to find the perfect fuel pump for your vehicle, visit https://www.kemsoracing.com/ today.