Failed ignition coil packs or spark plug resistors can cause a rough running motor or lack of power.
Problem Reports » Rough running motor/lack of power due to failed ignition coil packs/spark plug resistors
Car Problem Reports
Mercedes-Benz S320 Rough running motor/lack of power due to failed ignition coil packs/spark plug resistors
Mercedes-Benz S320 Problem
Visitor, 1996 Mercedes-Benz S320
i changed my coils and spark plugs and wires and engine light still on and car is mis firing
Coil number 6 failed and was replaced - now at 117000, other 2 coils failed also