What are the reasons for a car consuming more and more fuel?

[Olga]

There may be several reasons why a car is consuming more and more fuel: 1. Poor driving habits: Bad driving habits such as squeezing into gaps, sudden stops and starts, and driving at high speeds in low gears can all lead to high fuel consumption. To save fuel, try to maintain a steady speed and rely on inertia for braking. 2. Engine carbon buildup: Carbon buildup in the engine can also cause high fuel consumption. Consider purchasing car cleaning products to remove the carbon deposits from the engine, which can help reduce fuel consumption. 3. Low tire pressure: Low tire pressure or insufficient tire inflation can also cause the car to consume more fuel. Before driving, check the tire inflation. There are instruments available to measure tire pressure. Timely inflation of the tires can help reduce fuel consumption. 4. Overloaded trunk: Carrying too many items in the trunk can also increase fuel consumption. Regularly clean out the trunk and remove unnecessary items to lighten the load on your car, which will naturally reduce fuel consumption.

[JosephineLynn]

As a veteran driver with over a decade of experience, a sudden increase in fuel consumption should definitely raise alarm. The most common issue is driving habits—I've seen many drivers stomp on the accelerator and brake aggressively, a driving style akin to throwing cash straight into the fuel tank. Another culprit is low tire pressure; just 0.5 psi below the standard can increase fuel consumption by 3%, something I've verified multiple times with a tire pressure gauge. Frequent short-distance driving is another problem—if the engine doesn’t even reach operating temperature before you arrive, carbon buildup becomes severe. Using the wrong oil viscosity is also a hidden fuel-guzzler, especially high-viscosity oil in winter. Lastly, sensor issues like a faulty oxygen sensor sending false data can cause the ECU to over-fuel, easily exposed with a diagnostic tool. During regular maintenance, ask your mechanic to check spark plugs and air filters—these small components matter more than you think.

[LaBentley]

I usually pay close attention to vehicle expenses, but only recently noticed the issue when my refueling frequency significantly increased. First, the weight factor: the trunk has been carrying unnecessary items like tents and fishing gear year-round, equivalent to having an extra adult in the car. The tire pressure monitoring revealed that the right rear tire was underinflated, increasing rolling resistance and fuel consumption. In city commuting with frequent traffic lights, idling for over two minutes burns more fuel than restarting the engine—turning off the AC didn’t help either. After the last maintenance, using high-viscosity oil made the engine work noticeably harder. Another issue was my fueling habit: frequently filling up at non-standard gas stations with low-quality gasoline, which clogged the catalytic converter. Now, I consistently use fuel system cleaner every three months and switched to double-platinum spark plugs, gradually reducing fuel consumption.

[LeAdelyn]

Often helping friends check and repair cars, I've found that increased fuel consumption usually comes down to these common pitfalls: Engine carbon buildup thick as a concrete wall, causing fuel injection efficiency to plummet. The air filter dirty like a black sponge, restricting air intake. Spark plug gaps too narrow, resulting in insufficient ignition energy. Wheel alignment off, causing tires to crab-walk sideways. Oxygen sensors poisoned by lead, making the ECU miscalculate fuel injection. Brake calipers slightly stuck, dragging the brakes while driving. Don't underestimate these issues - addressing the whole set can easily increase fuel consumption by 20%. I recommend cleaning the throttle body every 20,000 km, which is far more effective than using fuel additives.

[NadiaLee]

From the perspective of automotive structure, increased fuel consumption is likely due to issues in the energy system. For example, clogged fuel injectors leading to poor atomization and incomplete combustion of gasoline. A constantly running cooling fan or a faulty thermostat causing the engine to operate at low temperatures for extended periods. A blocked crankcase forced ventilation valve allowing oil vapor to enter the combustion chamber. Automatic transmission shifting jerks or torque converter slippage wasting power. Worn universal joints on the drive shaft can also increase driving resistance. The most hidden issue I've encountered is an aging fuel tank cap seal, causing fuel vapor leakage and insufficient fuel pressure, prompting the ECU to increase fuel injection as compensation. These problems can be diagnosed more efficiently by checking fault codes with an OBD scanner, saving significant troubleshooting time.

[KiaraLynn]

Recently worked on an old car with a fuel consumption of 15 liters per 100 km and discovered several common causes: First, a faulty mass airflow sensor showing readings 30% lower than actual, causing the ECU to compensate by increasing fuel injection. Frequent short-distance driving led to oil emulsification, reducing lubrication and increasing friction. A clogged exhaust system with a broken catalytic converter blocked the exhaust pipe. Worn-out engine mounts increased vibrations, affecting combustion efficiency. Using the wrong oil grade caused abnormal operation of the hydraulic lifters in the camshaft. These seemingly minor issues combined can spike fuel consumption by up to 40%. Regular transmission fluid changes, carbon deposit cleaning, and sensor checks can significantly improve the situation.