Hello guys i dont know if you can help me i have a 2003 g35 auto , i really like my car and its the only way of transportation , yesterday when i turn off the car i could hear a knock sound it was loud it knock like 3 times i went and test drive the car and it feels right but i dont like that sound :/ when i was in a red light i did a fast aceleration and i hear the noise ones :/ thank u (sorry for my english is not that good)