如果车辆没其他异常，又超过3万公里没清洗积碳，那很可能就是积碳问题，清洗节气门、进气道积碳一般就能恢复原先的油耗。
If there are no other abnormalities in the vehicle, and the carbon deposit is not cleaned after more than 30000 km, it is probably a carbon deposit problem. Cleaning the throttle valve and the carbon deposit in the air inlet can generally restore the original fuel consumption.
In addition to carbon deposition, Jinan Benz auto maintenance personnel believe that there are several common fault points:
1、火花塞性能下降或损坏：这个很好理解，火花塞不好会造成燃烧不充分，自然产生的能量就低，就需要更多的油。同时还会加快积碳的形成，从而形成恶性循环。
1. Spark plug performance degradation or damage: It is well understood that a poor spark plug will lead to insufficient combustion, low energy generated naturally, and more oil is needed. At the same time, it will also accelerate the formation of carbon deposits, thus forming a vicious circle.
2、喷油嘴积碳或损坏：当下瞬时的喷油量是发动机电脑精确计算过的，如果喷油嘴有问题，会对喷油量造成浪费，增加油耗。
2. Carbon deposition or damage of fuel injection nozzle: the instantaneous fuel injection quantity is accurately calculated by the engine computer. If there is a problem with the fuel injection nozzle, it will waste the fuel injection quantity and increase fuel consumption.
3、前氧传感器故障：前氧传感器测得的尾气氧含量，是发动机电脑计算喷油量很重要的一个参数，如果信号不准，容易影响油耗。
3. Fault of front oxygen sensor: the exhaust oxygen content measured by the front oxygen sensor is an important parameter for the engine computer to calculate the fuel injection quantity. If the signal is inaccurate, it is easy to affect the fuel consumption.
4、节温器或水温传感器故障：发动机低温时，为了更快让发动机到达工作温度，会多喷油来应对。如果节温器一直开启，导致水温低，或者水温传感器损坏，一直给发动机反馈的信号就是温度低，那就会一直加浓喷油，从而造成油耗高。
4. Thermostat or water temperature sensor failure: when the engine is cold, more fuel will be injected to make the engine reach the operating temperature faster. If the thermostat is always open, resulting in low water temperature, or the water temperature sensor is damaged, and the signal always fed back to the engine is low temperature, then fuel injection will always be enriched, resulting in high fuel consumption.
The above points can be said to be very common reasons. Also, the air filter element is blocked, the oil viscosity is too high, and the brake wheel cylinder returns poorly. Come to our website if you have any notes http://www.lutongqixiu.com Consult!
