strange noise and rough idle

hi
When starting the car, there was a loud noise from the engine
Sounded like Phak!
kinda mechanical or electrical noise
dunno what happened
then, started it again, it didnt start
started it again, it runs, but idle is rough
so, i preferred to stop and phone my auto mechanic
he said its the fuel pump!

i think he is right
but what was the noise?

hi
When starting the car, there was a loud noise from the engine
Sounded like Phak!
kinda mechanical or electrical noise
dunno what happened
then, started it again, it didnt start
started it again, it runs, but idle is rough
so, i preferred to stop and phone my auto mechanic
he said its the fuel pump!

i think he is right
but what was the noise?

i repaired the thing myself
it was only a hose which was loose
i think its a hose which delivers air to the engine
so, when it does not get sufficient air, it has rough idle

but the fuel pump need replacement,as it whines
amm