Engine misfires (rough running) and lack of power are commonly caused by ignition coil pack or ignition module faults. Proper diagnoses should isolate the cause and prevent unnecessary replacement of good parts.Google+
Car Problem Reports
Mercedes-Benz SL65 AMG Rough Running Motor/Lack of Power Due to Coil Pack/Ignition Module Failure
Mercedes-Benz SL65 AMG Problem
Average Mileage: 36,304 mi (22,000 mi - 47,025 mi)
Visitor, 2005 Mercedes-Benz SL65 AMG, 47,025 mi
When you first start the car up, it runs fine while idling. Once you drive away and give the car some gas, it goes into limp mode and runs rough. When checking the check engine code using a OBD code reader, it is reported to be a "random misfire".
Visitor, 2005 Mercedes-Benz SL65 AMG, 39,800 mi
when you shut the car off after you run it the engine lacks power and no turbo. After you shut it off and reset the computer it works fine.
Visitor, 2005 Mercedes-Benz SL65 AMG, 44,000 mi
Check engine light, low power, no acceleration. MB dealership replaced a coil. Car infrequently driven. Problem returned, MB dealership found low voltage and misfire codes. Replaced batteries and followed recommendation to drive car more often. After a fantastic performance, the check engine light came on and car went into low power mode again. Very frustrating.
Visitor, 2006 Mercedes-Benz SL65 AMG, 22,000 mi
Misfiring and poor power will never occur on cold start, I know the problem the ethanol in gas is vaporizing in the engine and fumes are being used to start car. I had the dealer under warranty replace almost every part in the engine and not a change, until I pumped non-ethanol fuel and Walla, the problems is fixed. I am speaking to MB Customer service to fix my problem or buy back my car. I was never told when I bought the car that ethanol fuel (which is all there is in Miami, FL) would cause my car to be useless. Good luck and call Mercedes Customer Service and Complain, they will act like they never heard of this before, But I already know of Three cases. Insist or have your Local Lawyer file suit....
Misfires, limp mode, CEL, backfires.......