How to Improve Gas Mileage in Your 2019-2024 Ram 1500 5.7 HEMI Without Killing Performance

Owning a 2019-2024 Ram 1500 with the 5.7L HEMI means enjoying V8 power and capability, but it also means dealing with fuel economy that often lags behind its Ford F-150 and GM LS competitors. The HEMI’s performance is undeniable, but many owners find themselves looking for ways to stretch their fuel mileage without sacrificing the truck’s power. Fortunately, with the right upgrades and driving habits, you can improve gas mileage while keeping the performance you rely on.

1. Optimize Your Tuning for Efficiency and Power

• ECU Tuning: A custom tune can recalibrate your truck’s engine management system for better fuel economy while maintaining power. Performance tuners like the Edge Insight CTS3 allow you to adjust fuel maps and throttle response, and we’ve seen enough reports that tell us tuners offer a LOT of improvement in a lot of areas with the Hemi, including fuel economy.
• Throttle Controllers: Reducing throttle lag improves responsiveness, meaning you don’t have to overcompensate with excessive acceleration. Check out this one from Pedal Commander.
• MDS (Multi-Displacement System) Adjustments: The 5.7 HEMI features a cylinder deactivation system, but many owners disable it due to rough operation or reliability concerns. If you keep MDS active, ensuring the system is functioning properly can help maximize highway fuel economy.

2. Lighten the Load and Reduce Drag

• Ditch Unnecessary Weight: Removing excess cargo, heavy toolboxes, or unused bed racks can improve fuel efficiency. Every 100 pounds can reduce MPG by about 1%.
• Aerodynamics Matter:
• Installing a tonneau cover reduces wind resistance in the bed, improving MPG.
• Removing roof racks and accessories when not in use minimizes drag.
• Using lower-profile highway terrain (H/T) tires instead of aggressive off-road treads enhances aerodynamics.

3. Improve Engine Breathing with Better Airflow

• Cold Air Intakes (CAI): A high-quality Cold Air Intake improves airflow efficiency, leading to better combustion and slight MPG gains.
• High-Flow Air Filters: Replacing your factory air filter with a high-flow option ensures better air intake efficiency.
• Exhaust Upgrades: A cat-back exhaust system reduces backpressure and helps the engine breathe more efficiently, leading to potential gains in both power and MPG.

4. Upgrade Your Drivetrain for Efficiency

• Re-Gear for Highway Driving: If you’ve added oversized tires, re-gearing your truck’s differential can restore fuel efficiency and can put your truck’s engine back in the power band.
• Synthetic Fluids: Switching to synthetic oil, transmission fluid, and differential fluid reduces friction, improving efficiency and longevity. We’ve proven this in our own testing several times, switching from “real” 75/140 to a synthetic 80/90 netted us an extra 2 mpg just doing some basic maintenance.

5. Choose the Right Tires and Wheels

• Go with Low Rolling Resistance Tires: Highway terrain (H/T) or all-season tires have less rolling resistance than aggressive all-terrain (A/T) or mud-terrain (M/T) tires. Now, this is the truth, but the other truth is they don’t look nearly as cool and won’t give you the stance you want. BUT, we have to mention it, too. If you’re going for the best MPGs, the tires you run will have an impact.
• Proper Tire Pressure: Underinflated tires increase rolling resistance, decreasing fuel efficiency. Keeping tires properly inflated according to manufacturer recommendations can improve MPG by up to 3%.
• Lightweight Wheels: Swapping out heavy steel wheels for lightweight aluminum alloys can reduce rotational mass, improving acceleration and fuel efficiency AND look sweet in the process. It’s easy to say that “unsprung weight” – wheels and tires – doesn’t impact things, but that’s wrong. Turning fifty pounds of wheels and tires on each corner takes a lot less energy than ninety pounds of steel wheels and rubber.

6. Smart Driving Habits to Maximize Fuel Economy

• Use Cruise Control: Maintaining a steady speed prevents unnecessary acceleration and braking, helping conserve fuel.
• Avoid Excessive Idling: Trucks burn fuel even when not moving. Turn off the engine if you’ll be parked for more than a minute.
• Accelerate Smoothly: Rapid acceleration burns more fuel. Gradual acceleration and coasting to stops improve efficiency.
• Plan Your Routes: Avoid stop-and-go traffic when possible and use navigation apps to find the most efficient routes.

7. Maintain Your Truck for Peak Efficiency

• Regular Oil Changes: Fresh oil keeps the engine running smoothly, reducing internal resistance.
• Replace Spark Plugs & Ignition Components: Worn spark plugs and coils can cause misfires, leading to poor fuel economy. It’s easy to like the idea that “Coils either work or they don’t” but high quality coils can have an impact on your economy and power. Will you see a difference on the dyno? No, but hotter sparks can make a difference at the pump.
• Clean Your Fuel Injectors: That hotter spark from coils is going to be wasted if your combustion chambers are carboned up. Carbon buildup in the fuel injectors can cause inefficiencies, so buy gas from high-volume stations and use a high-quality fuel injector cleaner periodically.
• Check Your Oxygen Sensors: Bad O2 sensors can lead to incorrect fuel-air mixtures, hurting both performance and MPG, and what a lot of owners fail to realize is these units fail a lot faster than people think. If yours have more than 30,000 miles on them, it wouldn’t be a bad thing to swap them out. Yes, they’re a pain, and yes, they should last longer, but if you’re looking for those extra MPGs, it pays to know your O2 sensors are doing the job.

Balancing fuel economy and performance in your Ram 1500 5.7L HEMI is all about smart upgrades and good driving habits. A few strategic modifications—like better tuning, lighter components, and improved aerodynamics—can help maximize MPG without sacrificing the capability that makes your truck so useful.

Looking for the best fuel-saving upgrades? Check out our selection of tuners, intake systems, and performance parts at Stage 3 Motorsports!