Mercedes-Benz 560SEC oily spark plug causing rough idle issue on Mercedes-Benz 560SEC

Some Mercedes-Benz 560SEC owners report experiencing rough idle issues potentially caused by oily spark plugs, vacuum leaks, or ignition coil problems. Symptoms of a failing ignition coil may include the check engine light illuminating, poor engine performance, increased emissions, and difficulty starting the vehicle. Additionally, other factors such as fuel distributor, fuel injector, or idle controller issues can contribute to rough idle conditions. To resolve these problems, owners are advised to seek expert diagnostics and follow step-by-step repair solutions to ensure smooth engine performance. One common diagnostic test involves adjusting the mixture by disconnecting the EHA valve at the fuel distributor, which helps identify issues within the fuel system or ignition components. Addressing these concerns promptly is essential to prevent further complications.