Hello

I have 2003 C230 coupe. I live where it is cold. Recently I have found a strong odor of gas that comes into the cabin while idling or at a red light. I have looked under the hood and found no leak. At highway speeds the odor is gone but am assuming this is because of the air movement. While I was under the hood there was a very strong odor coming off the fuel rail with the injectors. I have search for answers to this and even brought it to the dealer. They said they need two hours to find the problem but most likely it is the leaky rings. Does this sound right?

THANK YOU