What are the reasons for a sudden increase in car fuel consumption?
3 Answers
Reasons for a sudden increase in car fuel consumption: 1. Oxygen sensor malfunction: If the increase in fuel consumption is not caused by poor driving habits, it is advisable to check whether the car's oxygen sensor is damaged or malfunctioning. In case of a fault, the oxygen sensor fails to function properly, leading to incorrect feedback on the car's exhaust emissions. For example, incomplete fuel combustion or insufficient power output may cause the car's computer to collect erroneous data, resulting in an increase in fuel injection and progressively higher fuel consumption over time. If the oxygen sensor is faulty, it can be cleaned or replaced with a new one. 2. Spark plug malfunction: Under normal circumstances, the fuel consumption of a regular SUV is around 10 liters per 100 kilometers. If it suddenly increases, check whether the spark plugs are malfunctioning. Carbon deposits on the spark plugs can cause weak ignition or delayed ignition, leading to increased fuel injection and higher fuel consumption. 3. Charcoal canister malfunction: Another possibility is that the car's charcoal canister solenoid valve is malfunctioning. It is recommended to take the car to a 4S shop for inspection and replace the charcoal canister. Doing so should resolve the issue of high fuel consumption.
After driving for so many years, the most frustrating thing for me is a sudden spike in fuel consumption. Last month, I suddenly noticed the fuel tank was emptying unusually fast, and upon closer inspection, I found the tire pressure was 0.5 points lower. Underinflated tires increase rolling resistance, making it feel like driving on sand. Worn spark plugs are also a concern—insufficient ignition energy leads to incomplete fuel combustion. Carbon buildup is another hidden fuel guzzler, especially for cars frequently driven in the city; a blackened piston top can reduce combustion efficiency by 20%. Brake drag is another major issue—last week during wheel maintenance, I found the caliper spring plate rusted shut, no wonder the fuel consumption suddenly increased. The most easily overlooked culprit is actually the air conditioning system; running the AC in summer can increase fuel consumption by 20%. When I notice abnormal fuel consumption, I troubleshoot step by step from simple to complex—first checking tire pressure, then looking for engine warning lights.
When a car suddenly becomes more fuel-consuming, start by checking basic components. The first thing is to measure tire pressure—if it's below 2.0 bar, fuel consumption can increase by 5% to 10%. My car had this issue last time; the tires even felt flatter than others'. Next, inspect the air filter. If it doesn't let light through when held up to sunlight, it's time for a replacement. A clogged filter restricts airflow, like running with a mask on. If the spark plugs have covered 40,000 km, consider replacing them even if they're not faulty, as electrode erosion affects ignition performance. Also, check the engine oil condition—oil that's too viscous or degraded makes the engine work harder. Lastly, don’t overlook the load from the AC compressor, especially during summer traffic jams when running the AC consumes the most fuel. Buying a tire pressure gauge and an OBD scanner can help handle most situations without rushing to the repair shop.
