I have a 2000 F350 7.3L Diesel that I use to haul a truck camper so it doesn't get a lot of use, though I run it once a week or so if we're not out roaming the world. It takes awhile 30 seconds +/- for the oil pressure gauge to show pressure and the oil pressure light to go out. Should I be concerned? I know with gas motors you can pull the coil while and crank until oil pressure comes up. Is there a diesel equivalent? Thanks for your feedback.

 

Sounds like a sticky oil pressure sending switch.