Hello, I purchased a left over 2018 Yukon from my local dealer. When I accelerate I hear what I call a ping noise or rattle coming from the engine. Reminds me of the old days when I was young and needed a higher octane fuel for a muscle car. I brought it to the dealer and they said they could not make the noise, they didn't try very hard. Just thought I would reach out and see if anybody else is experiencing this issue.