Since I got the car in late July, there is a popping sound under the hood during normal to moderate acceleration at lower speeds (under 50). I don’t know what the problem is but suspect the turbo wastegates. The frequency of the popping increases with speed, so it varies with the rpms of the engine. It almost sounds like pulses (the fuel rail vibrating to the rate of the fuel injectors). I don’t know! My usual dealer’s service manager said that it is “normal” for a turbo, but conveniently didn’t have a car to compare it to. After 3 visits and 3 loaner cars (in the shop for 21 days total), I went to a second dealer today. Their service manager clearly heard it and he had another low mileage CT5-V on the lot. He drove both and said that the sound from my car was not heard on the other car. But, he really is not sure of what it is. So, I have another loaner car and am hoping that they can finally find the source of the problem. I just wanted to get this out there in case others have this problem or someone can point me in the right direction.