What is the reason for the idling of Toyota Highlander 2.0T cold car?

Because the engine is ignited too late, the combustible mixture in the cylinder can not be fully burned, and sometimes it burns in the exhaust pipe. The engine is calibrated to reduce idle speed, thus improving fuel economy and reducing emissions. The engine control unit adjusts the actuator at any time, occasionally causing slight jitter. It is easier to be detected at low idle speed. Fuel quality and carbon deposition in the intake system also have great influence on the idling stability of the engine.

Toyota Highlander engine

The running engine should be able to run evenly in the speed range of 700 to 900 revolutions per minute. If the minimum stable speed of the engine exceeds this speed range, or the engine is turned off and the speed is unstable within this speed range, it means that there is no idle speed or poor idle speed. The reason for the unstable idle speed is that the air intake system is faulty.

For example, the leakage of intake manifold or various valves leads to unstable idle speed, excessive scaling of throttle and intake leads to unstable idle speed, failure of idle air actuator leads to unstable idle speed, failure of fuel system leads to unstable idle speed, failure of ignition system leads to unstable idle speed, and failure of mechanical structure leads to unstable idle speed.

It is normal to occasionally have irregular slight jitter when idling, so don't worry too much. At the same time, in order to prevent abnormal idling, car owners and friends should use high-quality fuel to reduce the formation of carbon deposits, regularly go to the garage for maintenance, carry out serious and professional inspection and maintenance of the car, and regularly clean the air intake system to remove carbon deposits.