I checked fuel pressure today 70 psi at fast idle , also connected a piece of clear tygon tubing on the suction side fuel line to look for bubbles to check for any air leaks and found none .
IF I do not fill my water pump priming tank to pump water right off and start the engine and run it , it runs excellent rev's up real nice sounds great etc .
BUT once I fill the priming tank of the water pump and start pumping water that's when the engine bogs down and the rpm's slowly drifts up and down.
I've inspected everything on the water pump ( inlet screen , inlet pipe outlet pipes , inside water pump housing ) thats all clean , once I apply a load to the engine thats when it bogs down .
Use to be able to rev it up with no problem when I needed to pump water before this problem started .
Going to have to have a good diesel guy come check it I guess .