Why Does the Car Consume More Fuel After Maintenance?
2 Answers
Here are the reasons for increased fuel consumption after maintenance: 1. If the old engine oil is not completely drained during the oil change and new oil is added at the standard dosage, it may exceed the upper limit on the dipstick, leading to higher fuel consumption. 2. Incompatible spark plug model. If the spark plugs replaced during maintenance are not suitable for your vehicle's engine, it will inevitably affect engine performance, and in severe cases, may cause damage to the engine. 3. Throttle body not rematched. Failure to rematch the throttle body can also be one of the reasons for high fuel consumption. After cleaning the throttle body, the opening becomes larger. If the throttle body is not rematched and reset using a diagnostic tool, the engine will control the air intake and fuel injection based on the pre-cleaning opening parameters, resulting in unstable idle speed and increased fuel consumption.
With twenty years of experience in car repair, I've encountered many car owners complaining about increased fuel consumption after maintenance. Common causes include minor mistakes during maintenance that reduce engine efficiency, such as using the wrong oil viscosity, making the engine work harder; an improperly installed air filter affecting air intake and forcing the engine to consume more fuel; incorrectly installed spark plugs leading to poor ignition and fuel wastage; or the engine's ECU resetting and needing time to relearn driving habits, resulting in temporarily higher fuel consumption in the first few days. Improper tire pressure adjustment can also increase rolling resistance. If the oil grade doesn't match or the filter quality is poor, it can add extra burden to the engine. It's advisable to first check the maintenance sheet to verify the oil specifications and items, ensuring no inappropriate materials were used. If fuel consumption doesn't return to normal within one or two weeks, be sure to visit a professional shop to check the data stream with a diagnostic tool. Don't ignore the issue, as it can harm the engine, waste fuel, and shorten the lifespan of components.
