So I went out to start my car this morning, and out of nowhere it would rev high, and then dip way down a couple seconds later (a difference of around 200-300 RPMs) and feel shaky like it was going to die. While it was revving high, I was getting a hollow, throaty sound coming from my intake that was way different than usual. This lasted about 3 minutes, and then finally evened out at about 800 rpms. Would this be from sitting for a couple days out in cold weather, and it just needed to warm up a bit? Sorry for the stupid question, but it really caught me off guard because it was OBVIOUSLY not right.