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 SLK32 AMG Bad Spark Plug Wires/Ignition Coils May Cause Misfires and Possible CEL
Mercedes-Benz SLK32 AMG Problem
Average Mileage: 92,050 mi (81,100 mi - 103,000 mi)
Visitor, 2002 Mercedes-Benz SLK32 AMG, 81,100 mi
Code p0303 p0300 ; rough idle almost to a stall at stop streets. Smooths out under acceleration.