My truck runs great and is super strong whenm cold and when hot but when wrming up it runs like a turd and is pretty undriveable until hot. 1991 chev 4x4 350/ auto. It is not flashing any codes at me but something is wrong. It lurches and coughs until I can rev it up a couple times. It is like a stuck choke but it's fuel injected?????? Please help me my chevy runs like a ford