What Causes High Idle Speed in Volkswagen Vehicles That Returns to Normal After Restarting?
2 Answers
Here are the specific reasons why a Volkswagen may have high idle speed that returns to normal after restarting: 1. Intake manifold leakage: When unwanted air, gasoline vapor, or exhaust gases enter the intake manifold, it can cause the air-fuel mixture to become too rich or too lean, resulting in unstable idle speed. 2. Excessive carbon buildup in the throttle body: Too much carbon buildup in the throttle body and surrounding intake passages changes the cross-sectional area of the air passage, preventing the control unit from precisely regulating idle air intake. This can also lead to an overly rich or lean mixture, causing unstable idle speed. 3. Faulty intake system components: There are many components in the engine's intake system that can fail, such as the throttle motor, idle speed control motor, duty cycle solenoid valve, mass air flow sensor, or intake pressure sensor. Any of these faults can cause unstable idle speed. 4. Fuel system malfunctions: Issues like clogged fuel injectors, a blocked fuel filter, a clogged fuel pump strainer, a faulty fuel pressure regulator, or a blocked return fuel line can all lead to incorrect fuel injection, resulting in an overly rich or lean mixture and unstable idle speed. 5. Ignition system problems: Faults such as a malfunctioning ignition module, incorrect spark plug gap, worn or damaged spark plug electrodes, or excessive resistance in high-tension wires can reduce spark energy or cause misfires, leading to erratic idle speed fluctuations.
Oh, I've encountered a similar situation before. The Volkswagen idles high and then returns to normal after a restart. This is usually because the electronic control unit gets a bit confused. It might be that the coolant temperature sensor misreads the temperature, making the ECU think the car is shivering from the cold, so it increases the idle speed. After a restart, the cache is reset, and it's as if nothing happened. Also, if there's a lot of carbon buildup clogging the throttle body, the computer gets tricked into acting erratically, and a restart clears some of the mess. When driving normally, remember to pay attention to whether the fuel consumption fluctuates abnormally. Don't just rely on restarts to solve the problem. Regularly cleaning the throttle body can prevent small issues from turning into big hazards.
