f250 stalls at idle

[robalo]

I have a 2006 f250 4stroke with 300 hrs the other day I ran from marina about 6miles 4500rpm when slowed down to idle it stalled would restart but stalled right away. In neutral it would run above 1000rpm so I finally turned the key fast enough and threw in gear and ran back to marina of course at dock same problem (made docking fun).I left at dealer to repair they say nothing wrong and no codes after 3 days they said to just run and bring back when it does it again(easy for them to say)It ran at full rpm on way back so I don't think fuel Its under warranty but they have changed or tried nothing so I have 100% chance of it happening again or make a educated guess and lower my chances I was thinking tps? I can't beleve It has no codes bu thats what they say.
Any Ideas?

[boats.net]

If not showing codes then could be a fuel related problem and if was somrthing like a vapor lock then may not even happen again, it is hard to say unless can test it when it is stalling out to find exact problem.