1.8 20v won't start

Hey everyone!

My ibiza 1.8 20v turbo won't start
I changed fuel pump relay, fuel filter and spark plugs
But it jump starts and then when a drive a while, then it will start with ease.
Is there a commen problem what to look for or fuel pump need to be replaced?

changed fuel pump but problem is still there.
it seems to be that it wont start when it is cold.
i have no idea what the problem is