2001 Chevrolet Diesel 3500 express van sta...

I'm having a fuel (?) problem with my van. I stall while driving or when idling or it doesn't start. Eventually it starts. Maybe I'm fooling myself but it seems to start after I empty the fuel filter and bleed it. Then it goes for a few days and dies again.
I dropped the fuel tank and there were flecks in it. I emptied the tank. I also cleaned (maybe not good enough) the fuel pump and put it back up, hoping I'd get through the winter and replace the tank in the spring.

The other day my fuel pump was making more noise than normal. Now it is quiet again.

Now I'm thinking the fuel injectors may be dirty. I don't even know where to look for them.

Where can I find a diagram of the fuel system of this?

Should I try to do it myself? I service oil burners and repair clocks so I'm not mechanically challenged.

Is there a way I can diagnose this. No "service engine soon" light that comes on and no codes.


Thanks
Marilyn