Beyond the normal engine tune factors--ignition, air filter, etc. you may need to check for a leaking cold start valve -- and with the CIS system fuel pressure is all important for proper running so you may need to check the line and running pressure to determine if the pump/and or the Control Pressure Regulator are up to snuff. Can you hear the frequency valve buzzing? If not, that's a sure sign the mixture is out of range. -- Dave