Cadillac DeVille engine missing at 55-65 MPH resolved by replacing cylinder #3 coil and plug, with ongoing oil leak issues on Cadillac DeVille

Some Cadillac DeVille owners report experiencing engine misfires, particularly at speeds between 55-65 MPH, which can often be resolved by replacing the cylinder #3 coil and plug. However, they also note that ongoing oil leak issues can exacerbate engine performance problems, leading to improper lubrication or spark plug contamination. This can further contribute to misfires and other performance-related issues. To tackle these oil leak problems, owners are advised to conduct a thorough inspection of the engine to identify the leak's source, which may involve components such as the head gasket or water pump. Addressing both the ignition system and the oil leak is crucial for ensuring optimal performance and reliability of the Cadillac DeVille.