What is the reason for the Buick 1.6t idling shake but not shaking when driving?

[McKaleb]

Buick 1.6t idling shake but not shaking when driving may be due to excessive carbon deposits inside the engine or prolonged use of spark plugs. Excessive carbon deposits in the engine: Excessive carbon deposits inside the engine can absorb a certain amount of fuel during startup, leading to a lean air-fuel mixture. When the carbon deposits become saturated with gasoline, the engine starts to operate normally. However, when the mixture is ignited, the gasoline absorbed by the carbon deposits is sucked into the cylinder by vacuum, causing the mixture to become too rich. This alternating lean and rich condition results in engine shaking. Prolonged use of spark plugs: Prolonged use of spark plugs can cause the spark plug gap to widen or excessive carbon buildup at the ignition point. These issues can lead to poor sparking or insufficient ignition energy, resulting in cylinder misfire, reduced power, and engine shaking.