2018 Ford Expedition Gas Mileage – Real-World Data And Efficiency
The 2018 Ford Expedition balances heavy-duty capability with modern fuel-saving technologies like an aluminum-alloy body and a 10-speed automatic transmission. While the EPA provides baseline estimates, your actual fuel economy depends heavily on maintenance, driving terrain, and how you manage the EcoBoost engine’s power.
You bought a full-size SUV to haul your family, tow your trailer, and maybe explore some backroads. However, seeing the fuel needle drop faster than expected can take the fun out of any road trip.
Maximizing your 2018 Ford Expedition gas mileage is entirely possible when you understand how the 3.5L EcoBoost engine works. This guide will help you identify the common “mileage killers” and show you how to keep your rig running efficiently.
We will cover everything from simple tire pressure checks to advanced maintenance that keeps your twin-turbo system healthy. Follow these steps to ensure you get the most out of every gallon you pump.
Understanding the 3.5L EcoBoost and 10-Speed Transmission
The 2018 model year marked a significant shift for the Expedition. Ford moved away from heavy steel and adopted an aluminum-alloy body, which shed about 300 pounds compared to previous generations.
Under the hood, you have the second-generation 3.5L EcoBoost V6. This engine uses both port and direct fuel injection to optimize power delivery and fuel atomization across the entire RPM range.
The 10R80 10-speed automatic transmission is the other half of the efficiency equation. It features a wide gear ratio spread and three overdrive gears to keep engine speeds low during highway cruising.
The Role of Turbocharging
Turbochargers allow a smaller engine to act like a large V8 when you need power. However, when the turbos are “in boost,” the engine consumes significantly more fuel to maintain the correct air-fuel ratio.
Staying out of the boost during daily commutes is the secret to hitting high efficiency numbers. Use a light touch on the accelerator to keep the wastegates from closing and forcing extra air into the cylinders.
Weight and Aerodynamics
Despite the weight savings, the Expedition is still a massive vehicle with the aerodynamic profile of a brick. At speeds over 65 MPH, wind resistance becomes the primary enemy of your fuel economy.
The 2018 model features active grille shutters that close at high speeds to reduce drag. Ensure these shutters are free of debris like leaves or plastic bags to keep the system functioning correctly.
Real-World 2018 Ford Expedition gas mileage Expectations
The EPA ratings for the 2018 Expedition generally sit at 17 MPG city and 24 MPG highway for rear-wheel-drive models. If you have a 4WD version, expect those numbers to dip slightly to 17 city and 22 highway.
In the real world, many owners report getting closer to 19 or 20 MPG on combined cycles. Achieving the higher end of the 2018 Ford Expedition gas mileage spectrum requires a disciplined foot and a well-maintained vehicle.
If you own the “Max” version (the extended wheelbase), the added weight and slightly different aerodynamics might shave another 1 MPG off your averages. Heavy cargo and full passenger loads will also have a noticeable impact.
City vs. Highway Performance
In stop-and-go traffic, the Expedition relies on its Auto Start-Stop technology to save fuel. This system shuts the engine off at red lights to prevent unnecessary idling.
On the highway, the 10-speed transmission excels. At 70 MPH, the engine should be spinning at relatively low RPMs, which is the “sweet spot” for the EcoBoost’s efficiency curve.
Towing and Payload Impacts
When you hook up a 9,000-pound trailer, don’t expect to see double-digit fuel economy. Towing usually drops the mileage down to the 8 to 11 MPG range depending on the frontal area of the trailer.
High-profile campers act like parachutes, creating immense drag. If you tow often, consider an equalizer hitch to keep the vehicle level and improve the aerodynamic profile of the entire setup.
Maintenance Strategies for 2018 Ford Expedition gas mileage
Maintenance is the most controllable factor in your fuel economy. A neglected engine has to work harder to produce the same amount of power, which wastes gas.
Start with your air filter. A clogged filter restricts airflow, forcing the engine to adjust fuel trims and often resulting in a “rich” condition that burns more fuel than necessary.
Check your tire pressure every month. For the 2018 Expedition, the door placard usually recommends 35-39 PSI depending on your tire size; low pressure increases rolling resistance significantly.
The Importance of Spark Plugs
EcoBoost engines are notoriously hard on spark plugs. The high cylinder pressures from the twin turbos can wear down the electrodes faster than in a naturally aspirated engine.
Inspect your plugs every 30,000 to 40,000 miles. Ensure the spark plug gap is set precisely to Ford’s specifications to prevent misfires and ensure a complete burn of the fuel mixture.
Cleaning the Sensors
The Mass Air Flow (MAF) or Manifold Absolute Pressure (MAP) sensors tell the computer how much air is entering the engine. If these sensors are dirty, the computer gets “lazy” data.
Use a specialized MAF sensor cleaner spray to remove oil and dust. Never use brake cleaner or carb cleaner, as these can damage the sensitive electronics inside the sensor housing.
Managing Carbon Buildup
Since the 2018 3.5L EcoBoost uses both port and direct injection, carbon buildup on the intake valves is less of an issue than in older models. However, it can still occur over high mileage.
Using a high-quality Top Tier fuel helps keep the port injectors clean. These injectors spray fuel over the valves, which provides a “washing” effect that prevents carbon from hardening.
Driving Habits to Improve 2018 Ford Expedition gas mileage
Your right foot is the most influential tool for saving gas. Small changes in how you approach intersections and hills can result in a 10-15% improvement in efficiency.
Avoid rapid acceleration from a stop. The 10-speed transmission is designed to shift early and often; let it do its job by maintaining a steady, moderate throttle position.
Use the Eco Mode setting found in the drive mode selector. This adjusts the throttle mapping and transmission shift points to prioritize fuel economy over raw performance.
Coasting and Anticipation
Look ahead at traffic lights. If you see a red light a quarter-mile away, take your foot off the gas and coast toward it rather than maintaining speed and braking late.
Coasting allows the fuel injectors to shut off completely while the vehicle is in motion (Deceleration Fuel Cut-Off). This is “free” mileage that adds up over a long commute.
Using Cruise Control Correctly
Cruise control is excellent on flat terrain. It maintains a steady speed and prevents the “surging” that often happens when driving manually.
However, in hilly areas, standard cruise control can be counterproductive. It may downshift aggressively to maintain speed on a climb, which spikes your 2018 Ford Expedition gas mileage downward.
The Impact of Modifications and Gear
Many owners love to customize their Expeditions for off-roading or camping. While these mods look great, they almost always come with a “fuel tax.”
Installing a leveling kit or a lift kit changes the angle of the vehicle. This allows more air to flow under the chassis, creating turbulence and increasing drag at highway speeds.
Larger, heavier tires are the biggest culprits. Moving from a standard highway tire to an All-Terrain (A/T) or Mud-Terrain (M/T) tire increases rotational mass and rolling resistance.
Roof Racks and Cargo Boxes
If you have a permanent roof rack or a cargo box, you are likely losing 1-2 MPG. The wind noise you hear is actually the sound of energy being wasted as the vehicle fights through the air.
Remove crossbars when they aren’t in use. If you must use a cargo box, look for low-profile designs that are shaped to minimize the aerodynamic wake behind the vehicle.
Aftermarket Exhaust and Intakes
Some owners install “cold air” intakes or high-flow exhausts hoping for better mileage. While these can improve engine breathing, the gains are often negligible unless the vehicle is tuned.
Be wary of “tunes” that promise massive MPG gains. Often, these tunes lean out the fuel mixture, which can lead to higher exhaust gas temperatures and potential engine damage under load.
Troubleshooting Low Fuel Economy
If you notice a sudden drop in your 2018 Ford Expedition gas mileage, it is time to do some detective work. A sudden 3-5 MPG loss usually indicates a mechanical or sensor issue.
Start by scanning for OBD-II codes. Even if the Check Engine Light isn’t on, there may be “pending” codes for things like a lazy O2 sensor or a small vacuum leak.
Check for “dragging” brakes. A sticking brake caliper can act like a constant anchor on your vehicle. After a drive, safely check if one wheel feels significantly hotter than the others.
Fuel Quality Issues
The 3.5L EcoBoost can run on 87-octane fuel, but it performs best on 91 or 93. Using lower octane fuel in hot weather or while towing may cause the computer to retard timing.
When the computer retards timing to prevent engine knock, efficiency drops. If you are struggling with mileage during the summer months, try a tank of premium fuel to see if the numbers improve.
Checking for Boost Leaks
Since this is a turbocharged engine, any leak in the charge pipes or intercooler will cause the turbos to work harder. This results in higher fuel consumption and reduced power.
Listen for a high-pitched whistling sound under acceleration. Inspect the rubber couplers and plastic piping for cracks or loose clamps that might be bleeding off pressurized air.
Frequently Asked Questions About 2018 Ford Expedition gas mileage
Does using “Sport Mode” ruin my gas mileage?
Yes, Sport Mode holds gears longer and keeps the engine at higher RPMs. It also sharpens throttle response, which usually leads to more aggressive driving and higher fuel consumption.
Should I turn off the Auto Start-Stop feature?
Turning it off will slightly decrease your city fuel economy. While some drivers find the restart sensation annoying, the system is designed to save fuel during long idles at traffic lights.
How much does 4WD affect my MPG?
The 4WD system adds weight and internal friction. Even when in 2WD mode, the 4WD Expedition typically gets about 1-2 MPG less than the RWD version due to the extra hardware it carries.
Will a tonneau cover help if I have an Expedition?
No, tonneau covers are for pickup trucks. For an Expedition, ensuring your rear spoiler and underbody shields are intact is the best way to manage airflow at the back of the vehicle.
Does the 2018 Expedition require premium gas for the best mileage?
While not required, the owner’s manual notes that premium fuel provides the best performance. In many cases, the increased efficiency of premium fuel can offset its higher cost per gallon.
Final Thoughts for the Efficient Owner
The 2018 Ford Expedition gas mileage is impressive for a vehicle of its size, but it requires an attentive owner to maintain those numbers. By staying on top of spark plug intervals and keeping your tires properly inflated, you can avoid the common pitfalls of SUV ownership.
Remember that the EcoBoost engine is highly sensitive to how you drive. Treat the gas pedal like there is an egg under it, and you will be surprised at how far a single tank can take you.
If you are planning a long road trip or a towing excursion, do a quick “once-over” of your filters and fluids. A healthy engine is an efficient engine, and a little DIY maintenance goes a long way.
Stay safe on the road, keep your sensors clean, and enjoy the power and efficiency of your Expedition!
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