sluggish when cold?

can anyone help me please
when my ford fiesta is stone cold it starts first time yet when i aplly the gas its sluggish and hardly moves the car forward, i have to then over gas the accellorater untill it kicks in it then is ok as long as the engine is hot.
i have tried new leads and new spark plugs also i have put in the petrol fuel injection redex but still i have the problem . i hope to hear from someone soon