I have a 1992 F350 with the 7.3 diesel in it. I bought it a few months back and had the oil and some fuel lines changed. I only drive it a few miles a day. Lately if I let it sit for more than a day or two it starts really rough and dies. If I press on the accelerator immediately and keep it between 500-1000 RPMs right as I start it, it does not die and starts to run normal in 10-20 seconds or so. I live in Northern CA (no snow in my city) and it does not get too cold. I am a rookie with diesels and really appreciate the help.

 

While this could be an issue of air intrusion, I suspect you've got one or two leaking injectors. Overnight, they leak down a bit, and it takes a few seconds of running to build up pressure again.
I had this before, and it got to the point where it was not firing on all cyls for the first 30s... go out there and find the injector which wasn't firing. I replaced it with another I had, and the problem got instantly better.

 

before you do any thing, park the truck and let it sit then the night before plug the block heater in and start it in the morning, if it still starts rough than it may not be glow plugs. if it starts good then carefully test the gp's. because it is likely bad gp's.