my vehicle is kicking when it's cold, stop when i gas

Hello, I bought a 207 diesel 2008 model vehicle. The problem of misfire started in the car for 1 month .. When the engine is cold, it stops when it passes 2500 rpm. ..

my teacher, a lot of things in the diesel car can cause to cold. Does the car emit blue smoke or white smoke from the exhaust when it first starts in the morning?

After working 3 minutes or so, it starts to smoke white