Reasons for BMW Idle Vibration When Parked

[LeJulianna]

Here are the reasons for engine idle vibration: 1. Aging engine components: Aging engine components, such as worn engine mounts, can cause body vibration. If the engine mounts are faulty, these vibrations will be transmitted to the steering wheel and the cabin. 2. Dirty engine throttle or excessive carbon buildup in the fuel injectors: When there is excessive carbon buildup, the gasoline sprayed by the cold start injector can be largely absorbed by the carbon deposits, resulting in an overly lean mixture during cold starts and making it difficult to start. After the engine starts, the gasoline adsorbed on the carbon deposits will be drawn into the cylinders by the engine's vacuum suction for combustion, making the mixture too rich. The engine's combustible mixture alternates between lean and rich, causing idle vibration.

[DiBeckett]

There are several common causes for BMW engine shaking during idle. From my experience, many owners encounter this issue, with the most prevalent being carbon buildup in the engine, particularly in the intake tract and throttle body. Carbon deposits can disrupt air intake, leading to unstable combustion. Another frequent culprit is deteriorated engine mounts. These rubber components act as vibration dampeners, but when they harden over time, engine vibrations get transmitted into the cabin. Spark plugs and ignition coils are also prime suspects, especially if they haven't been replaced after 70,000-80,000 kilometers. Weak ignition energy can cause misfires and shaking. Fuel system problems like clogged injectors or insufficient fuel pump pressure may also trigger vibrations. I recommend starting with a basic diagnostic scan to check for trouble codes, followed by carbon cleaning to assess improvement.