The same thing happened to me. It turned out to be a seal on the firewall that was never installed. I insisted the dealership replace my carpet which they did. But first they tried to bullshit me that the carpet would be fine because the matting underneath is a new material. Don't fall for that bullshit. Make them replace the carpet. They will tell you they have to get it cleared from district or some line of shit, but stick to your guns and they will buckle. Also they should give you a loaner car because it will take at least a week or so to get the carpet in. I think i was without my car for two weeks or so.