What Causes Intermittent Idle Vibration in the New Jetta?
1 Answers
Idle vibration is a common issue encountered in vehicles. If the owner notices significant body vibration when starting the vehicle or while the engine is running but the vehicle is stationary, it may indicate one of the following three conditions: 1. Severe engine carbon buildup: When there is excessive carbon buildup inside the engine, the gasoline sprayed by the cold-start injector can be largely absorbed by the carbon deposits, resulting in an overly lean air-fuel mixture during cold starts. This makes starting difficult, and the engine may only start easily once the carbon deposits are saturated with gasoline. After starting, the gasoline adsorbed on the carbon deposits is then drawn into the combustion chamber by the engine's vacuum, making the air-fuel mixture too rich. The fluctuating air-fuel mixture (alternating between lean and rich) causes idle vibration after a cold start. 2. Ignition system issues: Check the condition of the spark plugs, high-voltage wires, and ignition coils. Poor performance in the ignition system or weak spark plug firing can also lead to such symptoms. 3. Unstable fuel pressure: If you have already cleaned the engine carbon deposits, cleaned the throttle body, replaced the gaskets and spark plugs, but still experience body vibration at idle, it is recommended to visit a 4S shop to check the fuel supply pressure and the intake pressure sensor. Abnormal fuel pump pressure or incorrect readings and poor performance of the intake pressure sensor can also cause body vibration.
