Subaru Outback cold starting

hi, just bought a 2004 subaru outback 3.0. the problem is when cold ie when left for a few hours or overnight, i try to start the car normally by just cranking with no throttle the engine coughs a couple of times then nothing, i then try again cranking with no results, then i try but with the throttle down to the floor and after a few coughs and splutters it starts. the car will then drive great for the rest of the day starting first time every time, hope you can help thanks.