Why Your 2010 Expedition Gets Bad Gas Mileage (And How to Fix It)

How to Fix Poor Fuel Economy

If you're noticing your 2010 Ford Expedition is guzzling more gas than it should, you're not alone. Owners of this generation have reported a range of symptoms tied to declining fuel economy, often pointing back to the fuel system as a primary culprit. While a full-size SUV is never going to be a fuel-sipper, a sudden or significant drop in miles per gallon is a sign something is wrong. As one owner with a high-mileage example noted, persistence is key: "I've got a 2001 Expedition with 262,000 miles on the original engine and transmission. I just parked it this week because I'm waiting on a fuel pump to come in the mail and I ran the tank low." This highlights how addressing fuel system components is a critical part of long-term ownership and maintaining efficiency.

Symptoms

The first sign of a problem is usually watching the fuel gauge drop faster than it used to. You might find yourself filling up more frequently for your regular commute or trips. This isn't just a vague feeling; it's a measurable change. Calculate your MPG over a few tanks—if it's dropped significantly from what you used to get or from the truck's original EPA estimates, you have a concrete symptom.

Beyond just poor mileage, other drivability issues often accompany fuel system troubles. Owners report symptoms like engine misfires, where the engine stumbles or hesitates during acceleration. This misfire can cause a noticeable shaking or vibration, especially at idle or under load. An engine misfiring is not running efficiently, and unburned fuel is wasted, directly tanking your fuel economy.

In some cases, the issues can be more pronounced. You might detect raw fuel fumes, particularly near the vehicle or when the fuel tank is full. This is a serious symptom that suggests a leak in the fuel system, such as from a cracked line, a faulty seal on the fuel pump assembly, or a problem with the evaporative emissions (EVAP) system. Any fuel smell warrants immediate attention for both economic and safety reasons.

Most Likely Cause

Based on owner reports and discussions, the most likely cause of poor fuel economy in this truck is a failing component within the fuel system. The fuel system is a complex network designed to deliver the precise amount of fuel at the correct pressure to the engine. When any part of this system malfunctions, efficiency plummets. A weak fuel pump, for instance, may not provide adequate pressure, causing the engine to run lean. The engine computer (PCM) will then try to compensate, often by enriching the fuel mixture, which burns more gas. Similarly, a leaky fuel injector can drip fuel into a cylinder even when it shouldn't, or a failing fuel pressure regulator can disrupt the entire system's balance. These failures directly lead to the symptoms of misfires, shaking, and of course, poor MPG.

How to Diagnose

Diagnosing a fuel system issue requires a methodical approach. You'll need a basic scan tool and a fuel pressure test kit, which can often be rented from an auto parts store.

1. Check for Diagnostic Trouble Codes (DTCs): Use an OBD-II scanner to read any stored codes. Codes like P0171 (System Too Lean) or P0174 (Bank 2 Too Lean) can indicate a fuel delivery problem, while misfire codes (P0300-P0308) will point you to a specific cylinder.
2. Perform a Visual Inspection: With the engine off and cool, safely inspect the fuel lines running from the tank to the engine bay for any signs of wetness, cracking, or corrosion. Check around the fuel pump access cover (under the rear seats) and the fuel rail for leaks. Never ignore the smell of fuel.
3. Test Fuel Pressure: This is the most critical test. Connect your fuel pressure gauge to the Schrader valve on the fuel rail. With the key in the "ON" position (engine off), the pump should prime and pressure should spike and hold. Refer to your owner's manual or a repair database for the exact specification (typically between 35-65 PSI for this engine). Then, start the engine and note the pressure at idle. It should be stable. Finally, pinch the return line (if equipped) or have a helper rev the engine; pressure should increase. Pressure that is too low, too high, or that drops quickly after the pump shuts off indicates a faulty pump, a clogged filter, or a leaky pressure regulator.
4. Listen to the Fuel Pump: When you first turn the key to "ON," listen for a humming sound from the rear of the truck for 2-3 seconds. A loud whine, a weak sound, or silence suggests pump failure.

Step-by-Step Fix

Replacing a fuel pump assembly is a common repair for these issues. Here’s a general guide. Warning: Fuel is highly flammable. Work in a well-ventilated area, disconnect the battery, and have a fire extinguisher nearby.

1. Relieve Fuel System Pressure: Locate the fuel pump inertia switch (usually in the passenger footwell or rear quarter panel). Start the engine and let it run until it stalls from lack of fuel. Then, disconnect the negative battery terminal.
2. Access the Fuel Pump: The pump is located on top of the fuel tank. On the Expedition, you typically access it by removing the rear bench seat. Unbolt and carefully lift the seat out of the vehicle.
3. Remove the Access Cover: You'll see a large plastic or metal cover on the floor. Remove the bolts securing it. Clean the area thoroughly around the cover to prevent debris from falling into the tank.
4. Disconnect Electrical and Fuel Lines: Before disconnecting, note their orientations. Disconnect the electrical harness plug. Use a fuel line disconnect tool to carefully release the quick-connect fittings on the fuel supply and return lines. Have rags ready to catch minor fuel spillage.
5. Remove the Fuel Pump Locking Ring: This large plastic ring holds the pump assembly in the tank. Use a special spanner wrench or a brass punch and hammer to carefully loosen and unscrew the ring. As one owner preparing for a similar job shared: "They come with the bushings already. Only thing I can think of are new bolts and a cotter pin but im not sure what the bolts specifically are and whatnot." This mindset—ensuring you have all the right parts and fasteners—is crucial for a fuel pump job.
6. Extract the Pump Assembly: Carefully lift the pump assembly straight up and out of the tank. Be mindful of the float arm so you don't bend it. Tip the assembly to drain residual fuel back into the tank.
7. Transfer Components: If your new pump module doesn't come with a new fuel level sender (float) or seal, you may need to carefully transfer the old sender to the new assembly. Always use the new rubber seal/gasket that comes with the pump.
8. Install the New Pump: Lower the new assembly into the tank, aligning it properly. Hand-tighten the locking ring, then secure it with your tool. Reconnect the fuel lines and electrical connector.
9. Reassemble and Test: Reinstall the access cover and the rear seat. Reconnect the battery. Turn the key to "ON" (without starting) several times to let the new pump prime and pressurize the system. Check for leaks. Finally, start the engine and verify proper operation and fuel pressure.

Parts and Tools Needed

• Fuel Pump Assembly: Use a quality OEM-style replacement. A Motorcraft® part (like CW-2731 for some applications) is recommended for best fit and longevity. Confirm the exact part number for your 2010 Expedition's engine and drivetrain.
• Fuel Pump Seal/Gasket: This is critical and usually included with the pump.
• Basic Hand Tools: Sockets, ratchets, screwdrivers, pliers.
• Fuel Line Disconnect Tool Set: Essential for the quick-connect fittings without damaging them.
• Fuel Pump Locking Ring Spanner Wrench: Makes removing the ring much easier and safer than using improvised tools.
• Fuel Pressure Test Gauge: For diagnosis and verifying your repair.
• OBD-II Code Scanner
• Safety Gear: Safety glasses, nitrile gloves, and a fire extinguisher.

Real Owner Costs

The cost to fix fuel-related poor economy varies wildly based on the root cause and who does the work.

• DIY Fuel Pump Replacement: The part cost for a quality fuel pump assembly ranges from $150 to $400. If you already have basic tools, your only other investment is the specialty tools (disconnect set, spanner wrench), which can be rented or purchased for under $50. A successful DIY repair typically falls in the $200 - $450 range.
• Professional Fuel Pump Replacement: At a repair shop, you are paying for the part (marked up), 3-4 hours of labor, and shop supplies. Total bills commonly range from $800 to $1,200 or more, especially at a dealership. An owner acknowledging a common repair point noted: "Gotta do this fix on my 2010 Expedition. Ford really knows how to make 90% of a vehicle." This sentiment often reflects the frustration of facing a known, expensive repair.
• Other Repairs: Fixing a leaky fuel line or a single faulty fuel injector will be less expensive. Injector replacement might cost $300-$600 at a shop. However, diagnosing and fixing multiple issues or an EVAP system leak can add up, potentially reaching similar costs to a pump replacement.

Prevention

Preventing catastrophic fuel system failure is about maintenance and good habits. Never run your tank consistently to "E." The fuel pump is submerged in gasoline, which cools and lubricates it. Running on fumes causes the pump to overheat and fail prematurely. Try to refill when you have a quarter tank left. Using a quality fuel injector cleaner every 5,000-10,000 miles can help keep injectors from clogging. Finally, replace your fuel filter at the intervals specified in your owner's manual (often around 30,000 miles). A clogged filter makes the pump work harder, shortening its life.

What Owners Say

Real experiences from FORD owners:

Owner Experiences

"New Ford Expedition SUV Not the usual project car but just got this beast and gonna see what kind of mods I can pull off on this thing. 2004 Ford Expedition 5.4L Triton, 4wd, Hybrid Start key fob and push start), Automatic." — Due_Recording4733 (source)

"Not the usual project car but just got this beast and gonna see what kind of mods I can pull off on this thing. 2004 Ford Expedition 5.4L Triton, 4wd, Hybrid Start key fob and push start), Automatic." — Due_Recording4733 (source)

"I'm looking to get around a 1"-2" lift for my truck and I'm torn on what leaf pack I should go with. I don't carry much weight, so a medium duty pack would work for my purposes." — Gargarlord (source)

Real Repair Costs

"You get a little bag of like 20 of those for around $10-15. You can remove the old one out of the seat belt and place your new one in where you want it." — QuickCharisma15 (source)

"I bought one for my 2001 Expedition when I had it. You get a little bag of like 20 of those for around $10-15." — QuickCharisma15 (source)

FAQ

Q: How long does it take to replace a fuel pump? A: For a seasoned DIYer with the right tools, plan for 3 to 5 hours, taking your time to avoid mistakes. A professional mechanic will typically book 3-4 hours of labor for the job.

Q: Can I drive with poor fuel economy and a suspected fuel system issue? A: You can, but you shouldn't for long. Aside from wasting money on gas, you risk worsening the problem. A failing pump can leave you stranded. A fuel leak is a major fire hazard. If you experience severe misfires, shaking, or smell gas, stop driving and have it towed.

Q: Is poor fuel economy a common issue on the 2010 Expedition? A: While not a universal defect, fuel system components like pumps and injectors are wear items common to all vehicles. Given the age and mileage many of these trucks now have, failures leading to poor MPG are a frequent repair topic among owners in online forums and discussions.

Q: DIY vs mechanic – what's recommended for a fuel pump job? A: This is a mid-level DIY job. If you are comfortable with basic mechanics, have a safe workspace, and can follow detailed instructions, you can save significant money. However, the risks involve fuel and potential for leaks. If you are unsure, the peace of mind from a professional repair is worth the cost. As one owner learning a different repair wisely stated, having guidance is key: "Im replacing the front upper control arms on my 2001 expedition... I havent done it before but my master tech at my shop is going to show me next wednesday."

Q: Could it be something simpler, like spark plugs? A: Absolutely. Worn spark plugs can cause misfires and poor economy. Always start with the basics: check for codes, and consider a tune-up (plugs and coils) if it's been over 100,000 miles. However, the symptoms of fuel smell or confirmed low fuel pressure point directly to the fuel system.

Q: Will a new fuel pump immediately restore my original MPG? A: It will restore it to what is normal for your truck's current condition. If your fuel pump was failing, replacing it should bring your MPG back to its baseline. However, that baseline is affected by many other factors like tire pressure, alignment, air filter condition, and other engine wear. Don't expect brand-new truck mileage from a 14-year-old vehicle.