1992 Volkswagen Passat Not taking gas for about 10 - 15 sec

I just got this car, In the morning or after i shut it off for a bit the car will start no problem , but if i go to give it gas to move it just sits there tring to flood but never does. After about 10 -20 sec it goes no problem , if i keep the car on it works flawless. Any idea before i go for service call