my 7.3 draines its oil back in pan thus- loosing hi press oil and eng dies ,this makes it hard to start i took eng out of truck and removed pan pickup tube looks fine flang is tight where is my leak? anti siph?:

 

Sounds like a bad HPOP (High Pressure Oil Pump)

 

if step on throttle when i start trk it gets enough oil to fill high volume res and will stay running once its running it has good oil pressure somewhere im getting air in system i only have problems when it sets over nite