Lately when I first start my car in the mourning and put it in drive,The engine bucks and jerks for about 20 seconds and then smoothes out and is fine the rest of the day. I am not sure if it is due to the cold weather or not , does anyone know what would cause this?

Clean your IAC valve, and the rest of the throttlebody for that matter.

Change up those spark plugs too!

Make sure you turbo up-pipe isn't leaking!

what does IAC stand for? im getting the same sensation, however my engine light came on and its giving a fuel trim code and i cannot for the life of me figure out the problem, i was told its a vacume issue...any imput?

Idle Air Control / Idle Speed Control, Valve

MoreMGD32
If a vacuum leak has been confirmed, by either finding it, or hooking a vacuum gauge to the intake manifold - Fix the vacuum leak. Otherwise start another thread & post the code & symptoms, we'll help ya!