on cold days (below 40 degrees) when i first start my car in the morning the car will not idle. it will run like sh** then cut off, but it will only run if i keep my foot on the gas. once it cuts off i can crank it back up and it runs fine. and until the motor gets warm if you get into the gas a little it bucks and stumbles. but not like a misfire more like the motor is surging. car runs great other than that, im just lucky we're having a warm winter in NC.