Mine stumbles, idles wierd when stopped... it even makes the typical cluncking noise in the engine. The interior lights dim at stop lights. Sometimes the engine even makes a noise when I turn it off. All of this is normal. It has done this for 4 years since brand new. 50K miles later and everything is the same. Don't worry about it or try to find problems with the car. Everything is normal. If you want a quiet car that idles smooth, get a Lexus, Nissan or Toyota. If you want something with character made by some of the best engineers, keep the car. This is a noisy Mercedes! It takes a million quarts of oil. The parts are expensive! It may sound like it is falling apart when compared to Japanese cars, but it will probably live longer than most of us here. My dad has a 1976 350SL sports car and it sounds the same as my car! It has the same ticking type of noise. Just love the car and enjoy it. This car is a beast and it is just telling you it wants to take off at a stop light!