doesnt rerve up pass 2000rpm or 1800rpm every morning especilly when its cold

Hi guys please help me , my 96 hyundai tiburon 2lt 16v manual,doesnt rerve up pass 2000rpm or 1800rpm every morning especilly when its cold but when engine hot or during the day , cars fine.i have changed the leads coil pack new plugs car service. When the car idleing in the morning i remove the cold start switch to see if it works ,as soon as i do that the fan comes on so i pressume it works. Please help me.thanks Sugan