It not just about fuel filters, they do need to be done very frequently it's true (just one more diesel expense). What really matters is the fuel was stripped of the sulfur (lubricant) at the same time fuel pressure was dramatically increased as well as far more precise and tighter clearances in the moving parts so things wear out faster as well as clog up easier. It is the perfect storm and no amount of filter changes are going to replace the lost sulfur. I used to have a 12v with the old radial pump and no intercooler, I ran it on used motor oil, tranny fluid, gear oil... whatever was in the waste oil tank at the honda dealer I worked at, I cut it 50/50 with diesel fuel and it ran flawlessly for years, no way in heck you could do that with a cummins 24 valve or later. I call BS on all the guys claiming over 20MPG in a later cummins unless it is modified to remove emmisions programming and other equipment (more money into the bottomless pit) , I have owned, driven, borrowed a bunch and bone stock none would get close and I know how to milk good MPG from anything.