Hard to start car and after a little while the engine cuts out, why?

[jsb19]

hi got a m reg fiesta. i had it for about 3 months and everything been great but now the car wont start all the time. Sometimes i have to put my foot on the acc, or even jump start it from another car. If it does start and left for a while the engine cuts out. does anyone know why is is a could help me slove the problem. cheersthanks jame

[taillight]

When it stops see if you have spark and fuel pressure with a pressure guage.