hard start when parked for more than four hours

Is this a diesel engine? if so it sounds as if you fave a faulty glow plug, often if a glow plug has failed you will get the hard start and rough idle until that cylinder has heated up, normally just a min or so, ids this the case for you?

It is a petrol, there is one troubleshooting i just did this morning to diagnos my petrol pump if its working properly and i this it is weak, before i could crank my engine, i switch the key on to hear the fuel pump sound and turn it off, did it for a second tym and for the third time, the forth time i crank the engine it start same time, Dont you think i have to change my petrol pump?

Sounds as if there is a fuel rail pressure problem or a bleed back problem, best to get a fuel rail pressure test done to see how fast the pressure drops off and if you are getting correct pressure while the pump is running.

how does fuel rail pressure look like?

You will have to get a pressure gauge and attach it to the test port on the rail a mechanic will probably have to do this for you as a gauge is expensive to buy they need to look at line pressure and how much bleed back pressure there is over an hour or so

Thanks will try and do that, thanks once more again.

Please let us know how it goes so it will help others.

I tried that and still it did not work, someone advised me to change a fuel pump, accoding to his diagnosis the fuel pump is not faulty but its very weak, what do you think.

Yes that can cause the problem you are describing. Please let us know what you find