I have a 2007 CaseIH JX 80 it will run rough then smooth out and run fine ..it may run a couple of hours fine or it may only run 10 mins...I have drained and flushed fuel tank refilled with filtered fresh fuel...new fuel filters, clean screen on fuel pump. When it is running rough you can shut it down and remove filters drain them and reinstall and prime with hand pump then it runs fine for hours or min. you never can tell...when running rought rpm will go down from 2100 to 1900 up and down...it will do it when under a pto load like disc mower or baler or just sitting with no load...has 800 hours on it and just started this