Why is my 2005 2.0 engine hard to start, but runs fine?

Why is my 2005 2.0 engine hard to start, but runs fine? Engine cranks fine, sometimes I have to pump pedal to start. Sometimes starts right up, but usually cranks for a long time suggesting fuel draining out of system. Problem happens mostly after sitting for a while, when hot and has not been down long, will start right up.