Failed spark plug wires and/or ignition coils can cause intermittent misfires (rough running); the Check Engine Light may also illuminate. Diagnoses of the ignition system will be necessary to determine which components are at fault.Google+
Car Problem Reports
Mercedes-Benz C280 Bad Spark Plug Wires/Ignition Coils May Cause Misfires and Possible CEL
Mercedes-Benz C280 Problem
Average Mileage: 131,006 mi (74,000 mi - 187,777 mi)
Visitor, 1996 Mercedes-Benz C280, 187,777 mi
Changed spark plugs and wires misfire stopped.
Visitor, 1995 Mercedes-Benz C280, 160,000 mi
I just had my ingnition coil replaced, my car would not pick up speed.
Both spark plug harnesses replaced, one twice.
Visitor, 2000 Mercedes-Benz C280, 74,000 mi
Check engine light come on during dry periods. Drive the car through the car wash and the light goes off as it does when the road is wet or it rains.