Jetta is high and low when idling. What's the problem?

Jetta's idle speed is high and low, which is generally caused by excessive throttle wear.

1. What is idle speed?

Idle speed means that the engine runs with no load, and it only needs to overcome the friction resistance of its internal parts and does not output power to the outside. The lowest speed to maintain the stable operation of the engine is called idle speed, which is one of the five basic working conditions of the engine. The idle speed of an engine with good working performance is generally 550-800 rpm.

Second, the classification of idle speed

1. Normal idle speed

When the vehicle is parked and the engine is started, the lowest rotation speed of the engine running stably is called parking idle speed (the process that the engine changes from the idle state of cold car to the idle state that the engine reaches the normal working temperature is called warm car or hot car).

Step 2 drive at idle speed

When the car is in gear, the minimum opening of the throttle valve remains unchanged, and there is no need to step on the accelerator pedal or loosen it when driving. At this time, the engine speed is consistent with the parking idle speed, which is called driving idle speed.

3. Unstable idle speed

Idle instability is the most common fault in engine maintenance. If the diagnosis idea is incorrect, it will prolong the maintenance time, reduce the work efficiency, and even let the owner transfer to another garage without waiting.