In Atlanta, Ga. on a cold day (24 degrees), I had forgot to plug in my block heater. I had to recycle my glow plugs eight times without trying to start the motor before I got the motor started. There was a lot of white smoke, like a low cloud and the car ran very rough. I only use diesel fuel but in cold temperatures the diesel will gel and either not move at all and the engine will not run or move slow and engine will run rough. After running for at while the returning hot diesel warmed the fuel tank and the smoke went away and ran great as usual. You may also have one or more bad glow plugs as the glow plugs help smooth the engine until it warms up. If you have just one glow plug not working then your motor will run rough until the motor heats up.