E,

First remove fuel filters and check for contamination. Make sure there is no water. Check the fuel pump inlet and lines to see if there is a screen that could be blocked. The Kubota engine does not like any foreign materials in the fuel system. How many hours on the lift? When you checked the fuel injectors, did you remove the common rail? If so, was there any contamination in it? When installing the injectors back, were they installed in the correct cylinder they came out of?