What causes a 1998 buick century to have a dead spot when you start to drive when engine is cold ? Idles fine?

Dead spot gone after engine warms up. Engine light stay on but have had complete tune up 60 days ago.What causes a 1998 buick century to have a dead spot when you start to drive when engine is cold ? Idles fine?It may think it is a ford, they are cold nature also, It may be a sticking or bad heat riser, the flapper valve in the exhaust manifold the forces hot air up around the intake manifold to help atomize the gas vapors.A bad heat riser can cause a cold engine to run rough, and a stuck closes one can cause the engine to run hot. There are easy to miss on a tune up. I do not even know if they are still on newer cars, I will have to look and see.What causes a 1998 buick century to have a dead spot when you start to drive when engine is cold ? Idles fine?First and foremost, have the check engine light code revealed and it may give you a direction to go to resolve your problem. A coolant temp code could be telling you that you have a sensor problem. You have to start at the beginningWhat causes a 1998 buick century to have a dead spot when you start to drive when engine is cold ? Idles fine?The TPS sensor, coolant sensor, throttle plate sticking, God Bless