How to Boost MPG on a 5.4 Ford

The 5.4 liter Ford engine displaces 330 cubic inches. This modular engine (named for the manufacturing process, not an ability to interchange parts on the engine) was first introduced in 1997. Available in 2, 3 and 4 valve designs, the engine outputs anywhere from 260 horsepower (Ford F-series) to a supercharged 550 horsepower (Shelby Mustang) . The engine output, tuning, gearing, bolt-on additions and exhaust system all contribute to the fuel economy ratings of this engine. Actual fuel economy depends on individual driving habits, weather conditions, state of maintenance and aftermarket additions, which might improve or degrade mileage.


Step 1 - Inflate the tires to maximum cold pressure. Low tire pressure can reduce mileage by up to 15 percent. Keeping tires inflated to maximum cold pressure ratings reduces total drag on the vehicle and extends tire life.

Step 2 - Replace standard fluids with high quality synthetics when possible. Engine fluid, transmission fluid, gear box and differential fluid can all be replaced with synthetics to reduce total drag on the drive line. The 5.4 engine will have to work less to move the vehicle, resulting in higher mileage.

If you have driven over 90,000 miles, replace the spark plugs and fuel injectors. Spark plug gaps which exceed recommendations result in less efficient combustion. Fuel injectors, while they may still be functioning, degrade with wear and tear (fuel injector cleaner will remove deposits, but not remove wear). Replacing worn fuel injectors and spark plugs can result in mileage improvements of up to 10 percent.

Performance Tunes and Modifications

Step 1 - Remove drag inducing exterior modifications. Bug deflectors, rain guards, ground effects and step rails all increase drag on the vehicle. Increased wind resistance requires more fuel to maintain speed.

Step 2 - Install a Cold Air Intake system (CAI). Quality Cold Air Intake systems restrict and block much of the engine heat from warming the intake air. Cooler air is more dense, allowing more oxygen to enter the combustion chamber generating more energy during the fuel burn.

Step 3 - Wrap the exhaust manifold or headers with a quality exhaust wrap. Exhaust wraps insulate and prevent heat transfer from the exhaust manifold to the air intake system (manifold or engine compartment). Colder (and more dense) air provides more energy during combustion, resulting in less fuel consumed when accelerating and maintaining speed.

Step 4 - Replace the exhaust system. The 5.4L engine requires some back pressure in the exhaust (straight pipe exhausts will reduce mileage), but can benefit from increased exhaust flow. Increasing the diameter of the exhaust pipes by one half inch over stock may increase the performance of many 5.4L engine.

Performance tune the engine and transmission. Professional tuners can access your vehicle's on-board computer through the OBDII port (under the driver's side dash) with specialized programs to make performance adjustments. Fuel air rations, shift patterns, shift points and other optimizations for a given octane rating can increase fuel mileage (and performance) by 10 percent or more. Aftermarket hand-held devices such as DiabloSport, Superchips and Hypertech allow you to load custom tunes designed for your vehicle (and restore the factory tune if desired).

Adjust Driving Patterns & Habits

Step 1 - Reduce or eliminate aggressive driving habits. According to the U.S. Department of Energy, aggressive driving can reduce fuel economy by 5 to 33 percent. Moderate acceleration (not slow acceleration, which can decrease mileage), staying within speed limits, limiting highway speeds to 55 mph and coasting to stops (rather than maintaining speeds then braking) will reduce gas consumption.

Step 2 - Reduce vehicle weight. Removing items not needed for commuting (such as third row seats or bricks in the bed of the truck) can improve your mileage by as much as 2 percent for every 100 pounds removed.

Step 3 - Turn off the vehicle if you anticipate idling for long periods. Fuel consumed at idle significantly degrades overall mileage.

Step 4 - If equipped, avoid four-wheel drive, unless necessary. When the gears are engaged to turn all four wheels, the 5.4L engine will consume more fuel to accelerate and maintain speed.

Avoid ruts when driving in the rain. Drag produced by water on the tires may decrease mileage as much as 2 percent.

TIPS: If considering aftermarket additions primarily to improve fuel economy, the best cost-to-gain ratio is typically found with a performance tune.

THINGS YOU'LL NEED: Tire pressure gauge: Compressed air, New spark plugs, New fuel injectors, Synthetic replacement fluids

WARNINGS: Depending on the model of your Ford vehicle, your exhaust system or drive train may already be performance tuned (such as with the Shelby Mustang). Contact your local dealership or performance tuning specialists for specific vehicle information.

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