Why Is My Car Burning More Fuel Than Usual?

It seems you have realized it already you are spending a lot on fuel. The usage may have gradually increased or you may have suddenly got the idea that you were re-filling the tank more than once in a day from the fuel gauge. If so, then it is quite annoying and if you keep ignoring it, it will be very costly.

Good news is it will not always mean that your car is getting old. An increase in fuel consumption occurs mainly from things that can be changed a very minor fault, sometimes. In fact, spotting the culprit isn’t that difficult, really.

Your Tyres Might Be the Culprit

This one surprises a lot of people. Under-inflated tyres create more rolling resistance, which means your engine has to work harder just to keep the car moving. Also, when the engine is under more load, it consumes more fuel. Simple as that.

Check tyre pressure at least once a month. You’ll find the recommended PSI on a sticker inside your driver’s door or in the owner’s manual — not on the tyre itself (that number is the maximum, not the ideal). Even being 5–6 PSI low across all four tyres can noticeably affect your fuel economy.

A Dirty Air Filter Is Quietly Killing Your Mileage

For your car’s engine to perform optimally, it requires a balanced combination of air and fuel. Clogged air filters with accumulated dust, debris, and dirt result in the passage of a lesser amount of air, leading the engine to adjust by using more fuel to compensate for the shortage.

Changes of air filter do not cost much and are very convenient. Generally, mechanics advise replacing them every 15, 000 to 30, 000 kilometers. However, if you frequently drive in dusty environments, check your air filter more often. Remove it and inspect it against the light if you can’t see through it, it’s definitely time to change it.

Spark Plugs That Are Past Their Prime

Spark plugs play a vital role in the engine by igniting the fuel-air mixture. When they’re worn out or fouled, they don’t fire properly — and incomplete combustion means wasted fuel. You might also notice rough idling, sluggish acceleration, or occasional misfires alongside the increased fuel use.

Most modern cars need spark plug replacement somewhere between 60,000 and 100,000 kilometres, but older vehicles may need it more often. If you haven’t touched yours in a while and your mileage has dropped, this is worth looking at.

How You’re Driving Matters More Than You Think

OK, this is a bit personal, but hear me out. One of the ways aggressive driving habits significantly affect your car’s fuel consumption. Sudden acceleration, heavy braking, and operating the engine at high revs without moving will all cause you to consume more fuel as compared to driving smoothly and steadily.

If you keep on accelerating hard and then braking sharply at every light, you are virtually throwing fuel consumption away. It is better if you try to foresee the traffic in front of you, make a gentle acceleration, and allow the vehicle to coast for a while before braking. Getting used to it requires some effort, but the fuel economy change is quite genuine.

Furthermore, your speed on the highway matters a lot. The majority of cars reach their highest level of fuel efficiency at speeds between 80 and 100 km/h. If you increase it to 120 or more, the aerodynamic drag will be amplified to a large extent, and that will result in a sudden increase in fuel consumption.

The Oxygen Sensor Might Be Off

This is a less obvious one, but it’s surprisingly common. The oxygen sensor monitors how much oxygen is in your exhaust and sends that information to the engine’s computer, which then adjusts the fuel mixture accordingly.

A faulty oxygen sensor gives wrong readings, which causes the engine to run “rich” — meaning it injects more fuel than it actually needs. You might not notice any drivability issues at first, but your fuel economy takes a hit. Sometimes the check engine light comes on and other times it might not. Either way, if other causes have been ruled out, get the O2 sensor checked.

Old or Wrong Engine Oil

The engine oil provides lubrication to all the moving parts inside your engine. Over time, it degrades and gets contaminated, which increases friction and makes the engine work harder. Using the wrong viscosity oil — say, something thicker than what your car manufacturer recommends — can have the same effect.

Stick to the oil type specified in your owner’s manual, and don’t push oil changes further than recommended. This is basic maintenance, but it genuinely affects efficiency.

A Dragging Brake

Sometimes a brake caliper doesn’t release fully after you take your foot off the pedal. When this happens, the brake pad stays partially in contact with the rotor while you’re driving. You might not feel much difference in how the car drives, but the engine is constantly fighting that resistance — and burning extra fuel as a result.

One sign of this: the affected wheel area feels noticeably hot after a normal drive, or you notice a faint burning smell. If that’s happening, get it checked. Beyond the fuel waste, a dragging brake will also wear down your pads much faster.

AC Use and Short Trips

Running the air conditioning puts load on the engine and can reduce fuel economy by a noticeable margin, especially in city traffic. It’s not always avoidable — especially in a hot climate — but it’s worth knowing that frequent AC use does add up.

Short trips are also tougher on fuel economy than most people realise. Cold engines run less efficiently, and if your car never fully warms up before you reach your destination, you’re spending a lot of time in that less-efficient cold-start phase. If possible, combining several short errands into one longer trip helps.

So What Should You Do?

If your fuel consumption has gone up noticeably, start with the basics: check tyre pressure, look at the air filter, and think about when you last had a service. A lot of times it’s one of these simple things.

If the obvious stuff checks out, it’s worth getting a proper diagnostic done. Modern cars have a lot of sensors and systems that influence fuel economy, and a mechanic with a scan tool can quickly identify if something’s off. Don’t just live with the increased cost — chances are the fix is simpler and cheaper than you think.

Your car’s fuel efficiency is a pretty good indicator of its overall health. When it starts slipping, it’s usually the car’s way of telling you something needs attention. Better to sort it out early than wait until a minor issue becomes a major one.