PLEASE HELP,A CLASS 99 MODEL STARTS AND CUTS

[mia777]

PLEASE HELP,I HAVE A A140 CLASSIC ON T REG 99 MODEL THE CAR HAS DONE 89K ON THE CLOCK NOW IT HAS A PROBLEM,THE PROBLEM IS WHEN YOU START IT,IT STARTS AND CUTS OFF AGAIN YOU TRY IT DOES THE SAMETHING BUT WHEN YOU FORCE IT BY PRESSING THE ACCELERATOR IT WILL START AND IDLE WITH MISSFIRE UNTIL ATLEAST 5 MINUSTES,ONCE IT WARMS UP THEN IT REVS OK AND DRIVES OK BUT THE ENGINE STARTS TO SOUND LIKE A DIESEL ENGINES,I HAVE CHECKED THE OIL ITS BLACK OK NOT LIKE MILK AND THE WATER IS OK BUT I DONT KNOW WHAT IS CAUSING THIS,SOMEONE TOLD ME IT IS THE OIL PUMP FOR THE NOISY ENGINE BUT WHAT ABOUT THE STARTING BIT I THOUGHT MAYBE THE PETROL PUMP IS GONE BUT WHY DOES IT DRIVE AFTER ITS WARMED UP,SOMEONE PLEASE HELP ME