Just purchased a 964 that has not been used for about eight years although it went for a serviced once a year, The car is immaculate but it is incredibly hard to start when it is cold, you have to turn it over and over with it firing occasionally before eventually it will fire, it will then run fairly rough until it is warm, when it is it starts on the button when hot. I have put a fresh tank of petrol in and some injector cleaner it suffers occasionally from hesitation when you accelerate. Any ideas :?: