Hello, I recently purchased a 2000 SLK with 38,000 miles. Dispite many trips to the dealer, the engine continues to idle rough, with a rythmic shudder. It's not constant, and not all that noticeable, but it vibrates the whole car in 5-10 second intervals, and only when the car is at a stop. therwise she runs fine. The dealer has done many things including replacing the spark plugs and finally we replaced the entire engine computer (for about $1500). Anyone else have this experience or have suggestions? Thanks,-RHS