When I start my car in the cold the engine wants to immediatley shut off. I have to rev it lightly to keep the engine alive. I had my girlfriend do this when I had her start my car after climbing in thru the back seat (cause the locks were frozen)and noticed a poof of black exhaust come out of the muffler when she hit the gas. the smoke only came out once and the car idled fine after that. what could be going on here?
