How can I get better gas mileage in my 6.7 diesel?

In a 6.7-liter diesel pickup, you can improve fuel economy by focusing on maintenance, prudent driving habits, and sensible load management. The gains are typically modest but real, especially when you combine several small improvements over time.

This article explores concrete steps to improve efficiency in a 6.7L diesel, covering maintenance practices, driving behavior, weight and aerodynamics, fuel and additives, and considered upgrades. The goal is to help you optimize fuel economy without compromising reliability, towing capability, or emissions compliance.

Maintenance and Diesel Health

Keeping the engine and fuel system in top shape is the foundation of good mileage. A well-tuned diesel delivers cleaner combustion, steadier exhaust aftertreatment operation, and predictable fuel use. The following tasks are routinely recommended by manufacturers and diesel specialists.

These maintenance actions help sustain efficiency and prevent fuel-wasting issues:

• Follow the factory-recommended oil type and change intervals (synthetic 5W-40 is common for many 6.7L diesels). Regular oil changes support lubricity and cooler, smoother operation.


• Replace air filters when dirty or per service intervals to avoid restricted airflow that can raise fuel consumption.


• Replace fuel filters and perform fuel-system maintenance to keep injectors delivering clean, accurate fuel doses.


• Monitor and service the Diesel Exhaust Fluid (DEF) system and the diesel particulate filter (DPF) to maintain efficient exhaust aftertreatment and stable regeneration behavior.


• Address glow plug/ignition-related issues promptly to ensure clean starts and efficient combustion, especially in cold weather.

Regular maintenance minimizes avoidable fuel penalties and helps sustain expected efficiency over the vehicle’s life. If you tow or live in extreme climates, you may need more frequent service intervals as advised by the manual or a trusted technician.

Driving Habits and Route Planning

How you drive has a major impact on miles per gallon. Smart driving habits reduce fuel use without sacrificing performance when you need power for work or towing.

These driving practices tend to yield noticeable gains on the road:

• Maintain a steady speed on highways and use cruise control when appropriate to minimize accelerations and decelerations.


• Avoid rapid acceleration, excessive speeding, and hard braking, which waste diesel and trigger more frequent regen cycles.


• When towing, use the vehicle’s tow/haul mode and drive in a higher gear without under-revving the engine; keep engine load as efficient as possible.


• Plan trips to reduce number of cold starts and stop-and-go driving; combine errands to keep the engine in a warm operating window.


• Anticipate traffic, smooth out lane changes, and use highway lanes with consistent flow when feasible.

Adopting these habits helps you extract more miles per gallon across both city and highway driving, particularly when combined with proper maintenance and load management.

Weight, Payload, and Aerodynamics

Extra weight and aero drag are the stealthy drains on diesel efficiency. Reducing both where practical can lead to meaningful mpg gains, especially on highway runs and with lighter loads.

Strategies to trim drag and weight include:

• Remove unnecessary items from the cabin and bed when not needed and avoid carrying extra payload beyond what you truly require.


• Install a bed cover or tonneau cover to improve aerodynamics and reduce wind resistance behind the cab.


• Remove or minimize wind-catching accessories such as roof racks or crossbars when not in use.


• Keep tires properly inflated to the recommended cold pressures and ensure wheel alignment is within spec to minimize rolling resistance and drag.


• Use tires with low rolling resistance that match the vehicle’s load rating and driving conditions, and rotate them per the schedule to maintain efficiency.

Reducing weight and drag can offer incremental mileage improvements, especially on long highway trips where aero gains compound over distance.

Fuel, Additives, and Emissions Engagement

Fuel quality and controlled combustion play a direct role in diesel economy. Careful use of diesel fuel and compatible additives can help keep the system clean and efficient, while respecting emission controls.

Consider these points about fuel and additives:

• Use diesel fuel from reputable sources and avoid fuels with high water content; poor quality fuel can increase injector wear and reduce efficiency.


• Be cautious with fuel additives; some cleaners and cetane boosters can help maintain injector cleanliness and combustion efficiency, but results vary and not all products yield mpg improvements. Follow manufacturer guidance and test carefully.


• Ensure DEF is clean and properly used; proper DEF management supports smooth regeneration and exhaust functioning, which in turn supports stable efficiency.


• Diesel engines rely on accurate cetane and clean injectors for efficient combustion; if you notice rough running, knocking, or reduced MPG, consult a technician to diagnose fueling or injector issues.

Fuel quality and additive choices should be made with an eye toward emissions compliance, warranty considerations, and vehicle health. When in doubt, rely on a trusted diesel technician or your dealer for guidance tailored to your model year and drive profile.

Tuning, Upgrades, and Realistic Expectations

Some owners explore engine tuning or drivetrain upgrades to improve mileage. It’s important to weigh gains against potential risks, warranty implications, and compatibility with emissions systems.

For those considering modifications, here are common avenues and what to expect:

• ECU or performance tunes marketed for improved fuel economy can yield mpg gains in controlled conditions, but results vary and some tunes may increase exhaust temperatures, affect emissions, or impact warranty. Any tuning should come from reputable shops and be compliant with local regulations.


• Transmission or governor adjustments can optimize shift points for fuel efficiency; however, the impact depends on payload, towing, and terrain, and is best done with professional guidance.


• Gear ratio changes (e.g., different rear-end gears) can improve highway efficiency for heavy towing or high-speed cruising, but such changes are expensive and may reduce off-road or low-speed torque capability. Consider this only if you routinely carry heavy loads or tow long distances with highway emphasis.

Most drivers see the most reliable mpg gains from a combination of maintenance, driving discipline, and sensible weight/aero optimizations rather than aggressive performance changes. If you rely on the truck for frequent towing or heavy payloads, set realistic expectations for mpg and prioritize reliability.

Monitoring and Real-World Feedback

To know whether your changes are paying off, track fuel economy over several tanks and under similar conditions. Small variations are normal, but consistent trends point to what’s working for your truck and typical usage.

Consider establishing a baseline, then measuring after each major change (e.g., new air filter, tire pressure adjustment, or a new driving routine). This data-driven approach helps you identify the most effective tweaks for your specific setup.

Summary

Improving gas mileage on a 6.7 diesel comes from a blend of diligent maintenance, smarter driving, weight and aerodynamic discipline, careful fuel and additive choices, and, if pursued, selective upgrades. Expect incremental gains rather than dramatic leaps, especially when towing or carrying heavy loads. With consistent application, you can achieve noticeably better efficiency while preserving performance and reliability.

How can I increase my 6.7 Cummins MPG?

Hi. There are a couple things you can do. Start with a cold air intake kit. It will use a high flow reusable air filter. A larger exhaust will also help a little, and it will help to keep exhaust temperatures down. The biggest power and fuel mileage gains will come from a programmer.

How much MPG does a 6.7 Power Stroke delete add?

A1: Yes, deleting the DPF can increase MPG by 4-5 MPG on average, improving efficiency by up to 30%, especially during light or moderate load conditions. Q2: What are the benefits of deleting the DPF system on a 6.7 Powerstroke?

What is the gas mileage on a 6.7 Power Stroke?

A 6.7 Powerstroke engine's fuel mileage typically ranges from 12-18 MPG combined, though highway driving can achieve 17-20 MPG under optimal conditions. Actual mileage varies significantly based on factors like driving style, speed, load, and road conditions. 
You can watch this video to see a test of 6.7 Powerstroke fuel mileage on the highway: 59sworkplaytvYouTube · Aug 9, 2019
Factors affecting fuel mileage

• Driving conditions: Highway driving generally yields better mileage (17-20 MPG) compared to city or mixed driving, which is often around 12-18 MPG. 
• Speed: Higher speeds, especially above 75 mph, can decrease fuel efficiency. 
• Towing and load: Hauling heavy loads will reduce mileage significantly. For example, a driver reported getting as low as 7.5-8.0 MPG while towing a heavy load. 
• Vehicle configuration: Tire type (e.g., larger, more aggressive tires) and rear-end ratio can impact fuel economy. 
• Engine condition: Mileage can improve as the engine breaks in and is properly maintained. 

This video shows how towing affects the 6.7 Powerstroke fuel mileage: 58sPD Diesel PowerYouTube · Nov 6, 2024
Examples of real-world mileage

• Highway: Some drivers report achieving over 20 MPG on the highway, with ideal conditions leading to 21-22 MPG. 
• Mixed/City: A mix of city and highway driving often results in an average of 15.3-18.9 MPG. 
• Towing: Mileage drops significantly when towing, with one owner reporting 9.8-10.7 MPG while towing 8,000-12,000 lbs. 

How do I get better fuel mileage out of my 6.7 Power Stroke?

You can improve 6.7 Powerstroke fuel mileage by changing your driving habits, performing regular maintenance, and making certain modifications. Aggressive driving and excessive idling reduce fuel economy, while driving smoothly, using cruise control, and maintaining proper tire pressure can help. Regular maintenance, such as changing air filters and oil, is crucial, and some drivers see significant gains from engine tuning, a cold air intake, or a DPF delete (though the latter may have legal implications). 
This video demonstrates how to improve your fuel economy by changing your driving habits: 49sPower Stroke MaintenanceYouTube · Apr 25, 2023
Driving habits

• Drive smoothly: Avoid aggressive acceleration and hard braking. 
• Reduce high speeds: Driving at lower highway speeds, like 65 mph instead of 75 mph, can significantly improve mileage. 
• Avoid excessive idling: Let the engine warm up briefly and then drive, rather than idling for extended periods. 
• Use cruise control: Maintain a steady speed on the highway to avoid fluctuations. 

Maintenance and upkeep

• Change filters: Regularly replace the air filter and other maintenance items. 
• Keep up with oil changes: Ensure your engine oil is changed regularly. 
• Check tire pressure: Maintain correct tire pressure, as underinflated tires can decrease fuel efficiency. 

Modifications and tuning

• Engine tuning: Aftermarket tunes can optimize the engine's air-fuel ratio and injection timing for better efficiency. 
• Cold air intake: Upgrading to a cold air intake can improve air density, potentially leading to better fuel economy. 
• DPF delete: Some drivers report significant mileage improvements after removing the Diesel Particulate Filter, but this is often illegal and can have environmental consequences. 

This video shows how a DPF delete can affect your truck's performance and fuel economy: 59sTyler LanzYouTube · Oct 19, 2021