Did you get a diagnosis on your truck? I have the same identical issue with mine as you descibed at the top.

stop using starting fluid .... go get seafoam product called marine fogging oil..... wont blow up glow plugs...... use it in my tow truck when its really cold in idaho
but it also sounds like you glow plugs are either not working or your pump is not putting out much fuel..... try to pour just a little while cranking... see what that does