It sure sthateems like fuel problem. What concerns me is that it ran better for a while after changing the filter. A quick assumption would be the filter clogged again. That raises the question - WHY? Has it sat for a while? Is it old fuel ? Is there rust in the tenk. If I was to be dealinf with it I would look carefully in the tank for rust-dirt-an anything that isn't clean fuel ( I assume it is a deisel) . One problem that very few know about with deisel is algea -yes algea slimy groth like found on wet rocks. In deisels it is uaually brown -nasty sludge. I use an approved algacide once yearly in all my deisel tanks. If yuo find algea ,you are in for a tough cleaning and killing job. (And I mean tough) After using an algicide there will be dead "bugs" to clog the filter. You can't clean it enough. Let me know what you find.
