Routine Maintenance

• Regularly change the air filter. A clean air filter allows your engine to perform efficiently by ensuring optimal air intake.
• Maintain proper tire pressure. Under-inflated tires create more rolling resistance, increasing fuel consumption. Check tire pressure at least once a month.
• Ensure timely oil changes with the correct grade of oil. Using the recommended engine oil reduces friction and helps the engine run smoothly.
• Inspect and replace spark plugs as necessary. Worn-out spark plugs can lead to inefficient combustion, reducing fuel economy.

Driving Habits

• Avoid aggressive driving. Sudden starts and hard braking can significantly lower your fuel efficiency. Try to maintain a steady speed.
• Use cruise control on highways when possible. This will help maintain a constant speed, reducing fuel consumption.
• Plan your trips to avoid unnecessary idling. If you’re stopped for more than a minute or two, consider turning off the engine.
• Minimize load and reduce drag. Remove any unnecessary weight from the car and avoid using a roof rack unless necessary.
• Avoid using air conditioning excessively. At lower speeds, open windows might be more fuel-efficient than using the AC.

Technical Adjustments

• Ensure your vehicle’s alignment is correct. Misalignment can lead to drag and uneven tire wear, which reduces fuel efficiency.
• Keep your fuel injectors clean. Dirty injectors can disrupt the precise spray of fuel necessary for efficient combustion.
• Consider an ECU tune-up or re-flash. This can optimize the engine's performance for better fuel efficiency.
• Pay attention to warning lights on the dashboard. Ignoring them can lead to larger issues affecting efficiency.

Fuel Considerations

• Use the recommended octane fuel. Using a lower or higher octane fuel than recommended by Mercedes-Benz can lead to inefficient engine performance.
• Purchase fuel from reputable stations to ensure you’re getting clean, high-quality fuel that doesn't clog your injectors.
• Consider using fuel additives sparingly. Some can help clean the engine, but overuse may not yield additional benefits.

Overall, maintaining your 2021 Mercedes-Benz C-Class in peak condition through proper maintenance and smart driving habits will help maximize its fuel efficiency. Adopting a proactive approach ensures that your vehicle remains efficient and operates at its best.