hi recently with this very bad cold weather i noticed a weird smell comming from the vents in my car when i would have my heat on. The smell would come and go. I feel no difference with the performance and temperture gauge is fine no white smoke but i do get some smoke with a weird smell out the tail pipe. Im going to bring it in as soon as im off but i come here to get some kind of idea on what it could be so the mechanic wont tell me something out rageous. please get back to me on what you think it might be. thank you