Smart Fortwo oil on spark plugs causing engine power loss when slowing down on Smart Fortwo

Some Smart Fortwo owners report experiencing engine power loss due to oil on the spark plugs, particularly noticeable when slowing down. This common issue can significantly disrupt engine performance and longevity, as oil-soaked spark plugs interfere with the combustion process, leading to symptoms such as slow acceleration and heavy engine ignition. The presence of oil on the spark plug threads may indicate a leaking valve cover gasket, which requires inspection and repair by a mechanic. To assess whether oil is entering the combustion chamber, owners can remove the spark plugs to check for oil coverage. Promptly addressing this issue is essential for maintaining the vehicle's performance and health.