Everyone wants to burn less fuel, but it is hard to separate what works from myth. Here is what really affects consumption from a mechanic who looks at engines every day.
Tire Pressure
The simplest and most neglected factor. Under-inflated tires create more rolling resistance, forcing the engine to burn more fuel.
How much it matters: Just 0.5 bar below recommended can add 3 to 5 percent. Check once a month on cold tires. The recommended value is on a sticker inside the driver's door frame.
Regular Service
An engine running with a clogged air filter, old oil, or worn plugs simply burns more fuel.
Specifically: A clogged air filter can add 5 to 10 percent. Old oil increases friction. Worn plugs cause incomplete combustion. A regular minor service with quality parts pays for itself through lower consumption.
Driving Style
The biggest factor, and completely free. Aggressive acceleration and hard braking can add up to 30 percent in the city.
What helps: Accelerate gradually, hold a steady speed, use engine braking when you can. You do not have to drive slowly, just smoothly. On the highway, the gap between 120 and 140 km/h can be half a liter per 100 km.
Unnecessary Weight
Every extra kilogram requires energy. A trunk full of junk, roof rails out of season, a roof box. All burns fuel.
How much it matters: Empty roof rails alone can add 5 to 10 percent on the highway from drag. Take them off when you do not need them.
Air Conditioning
The AC uses fuel. That is a fact. But how much depends on the situation.
Realistically: In the city, the AC can add 0.5 to 1 liter per 100 km. On the highway the impact is smaller, and rolling the windows down creates aerodynamic drag that costs roughly the same as running the AC. On the highway, use the AC. In the city, open a window.
Fuel Quality
Cheap fuel from unverified stations may contain more water and contaminants. That not only increases consumption but can damage the injectors and the fuel pump.
Advice: Fill up at reputable stations. The price difference is minimal, and the engine will run better and burn less.
Engine Warm-Up
A common myth is that you need to idle the engine for a long time before driving. Modern engines are designed to warm up through gentle driving.
What to do: Start up, wait 15 to 20 seconds for oil to circulate, then drive gently. Avoid high RPMs for the first few minutes. Idling for 10 minutes just wastes fuel and accelerates soot buildup.
Myths to Forget
"Premium fuel reduces consumption in a regular engine." No. If your engine does not require premium, zero benefit. Just a higher price per liter.
"Driving in a lower gear saves fuel." No. Needlessly high RPMs burn more. Use the highest gear that allows comfortable operation.
"Turning off the engine at a traffic light saves fuel." Only if stopped for more than 30 to 40 seconds.
The Bottom Line
No magic trick. Regular service, proper tire pressure, and sensible driving together can cut consumption by 15 to 20 percent. If your car seems to burn more than it should, bring it in. Sometimes the cause is a faulty sensor or clogged EGR that the ECU compensates for by adding fuel.