1994 Jaguar XJ6 Car starting

In the morning my car always starts immediately. However to keep it going often I have to keep my foot on the gas for a couple of minutes. Black streaks often are left on the ground from the exhaust pipes. However once warmed up it never blows anything black nor does it smoke. However it does sound like it is puttering. Occasionally while driving it will cut off and stall. Every time I have been driving car and turn it off, it wont start it sounds as though it needs gas. I have to wait without trying to start the car for up to about 1 to 2 hours before it will start again. Once I see this is a real site and an applicable solution than Ill give an donations