What are the symptoms of the old Bora accelerator being broken?

The accelerator of Volkswagen Bora is broken. What happened? The throttle valve of Volkswagen Bora is damaged, and the symptoms are as follows: 1. The vehicle is shaking at idle speed, which makes it difficult to ignite when it is cold, and the tachometer indicates instability (unstable idle speed); 2. Reason: Oil vapor is the main reason. When the engine is running normally, there must be crankcase exhaust gas, especially when using relatively low-grade engine oil. In a particular design, one of the crankcase exhaust systems is connected to the front of the throttle. 3. It is likely that a part of the hot crankcase exhaust gas will return to the front of the throttle through the small hole. When idling, this hot crankcase exhaust gas gradually cools with the air intake, and finally the temperature is low enough to become an oil film deposited near the throttle. This oil film will further absorb dust and provide fuel for the flame, which will play a decisive role. 4. On the other hand, the other part of the crankcase exhaust system is connected with the throttle valve, and this exhaust gas will directly pollute the real empty pipeline, including the fuel regulator.