What Causes a Sudden Doubling in Fuel Consumption?

[DelIsabelle]

The reasons for a sudden increase in fuel consumption are as follows: 1. Severe Engine Carbon Deposits: Carbon deposits typically form on the fuel injectors, spark plugs, throttle valve, and combustion chamber. When carbon buildup reaches a certain level, it can cause difficulties in ignition, stalling during neutral coasting or gear shifting, poor acceleration, and unstable idle speed, fluctuating between high and low. 2. Use of Low-Quality Fuel: Since low-quality fuel contains more impurities, it cannot be fully combusted. As a result, a significant portion of the gasoline is expelled from the vehicle. Additionally, the oxygen sensor may develop a layer of white or reddish-brown deposits on its surface, leading to misjudgment of exhaust oxygen content and transmission of incorrect data, ultimately affecting the control of the fuel injection ratio. 3. Excessive Vehicle Load: Some drivers tend to carry unnecessary items in their vehicles, which increases the weight. Others prefer to fill the fuel tank to its maximum capacity, which also adds to the vehicle's weight. A heavier load increases the pressure of the tires on the ground, leading to greater tire friction. 4. Use of High-Power Electrical Devices: Especially during idle, when the engine speed is low, the generator may not produce sufficient electricity. Using high-power electrical devices (such as air conditioning or high-power audio systems) can place additional strain on the engine and battery. Operating the vehicle under high load conditions can also result in increased fuel consumption.

[LaReese]

When fuel consumption suddenly doubles, as someone who frequently repairs cars, my first thought is mechanical issues. It could be aging spark plugs causing poor ignition and incomplete combustion; a clogged air filter restricting engine intake, making it work harder and consume more fuel; low tire pressure increasing rolling resistance and slowing you down; or a faulty oxygen sensor misleading the computer into injecting more fuel. Additionally, a weak battery can affect the charging system, indirectly increasing fuel consumption. Don’t overlook changes in lubricant viscosity—excessive thickness can significantly increase resistance. In short, such problems require systematic inspection. It’s better to have a repair shop diagnose it early before a small issue becomes major. I recommend first checking the spark plugs and tires yourself, then consulting a professional for the sensor components.

[JaceFitz]

I've had personal experience where a sudden increase in fuel consumption is often related to changes in driving habits. For example, I've been busy lately and always drive impatiently, with sudden acceleration and braking, which unnecessarily consumes 20% more fuel; the air conditioning is turned up too high, especially under high summer temperatures when the system load doubles; or forgetting to turn off unnecessary functions like seat heating, which continuously consumes electricity. Additionally, increased load or rushing for urgent matters can also make the engine work harder. The solution is to try to drive more smoothly, maintain a constant speed, and regularly check the efficiency of the air conditioning system. Remember, small adjustments can save big money.

[GabrielFitz]

From an environmental perspective, doubled fuel consumption is often caused by external factors. I've observed that cold starts in winter require more fuel to warm up the engine, naturally increasing consumption. Poor road conditions like frequent stop-and-go traffic lead to engine idling, further worsening fuel usage. Seasonal air pressure changes can also affect the intake system. Worn tires create more resistance on slippery roads, and strong headwinds or uphill sections force the engine to work harder. Timely driving adjustments, such as warming up the car before moving, can help mitigate these issues.