Ford F-350 starting issue.. Please help!!
 

Hi everyone! I'm from Romania and I have a Ford F-350 KingRanch, 2003, 6.0l.
I have some problems with it, when the engine is cold, it starts very quickly but when it's warm it doesn't want to start, it start's only whith starting spray.
I took the truck to many mechanics but none of them know how to fix it! Maybe it's someone here who has had this problem and can help me!!
Excuse me if I wrote something wrong! Thank you !!!