a cold day after i got my PCV valve changed the car couldnt start up right away when its cold condition...but if i step on the gas for few sec it would be okay and stay on.....but if u just crank it normally it would just shut off....does it have anything to do with the PCV valve? what would be the cause?

 

To my knowledge the PCV just helps the crankcase breathe better. Check the connections of the PCV, its easy to make a mistake in that small area.