The finger pump has to develop real increasing resistance until you hear the relief valve on the injection pump open. This noise occured? It makes a detectable noise. This has to occur before accepting things are okay In the area. In itself it is a test. Sounds from your description it did but not certain. When the pressure does not increase and the squeal is not heard. Either the relief valve is open or the lift pump check valves are not sealing well enough.

If it did squeal valves checked are pretty much next. Or you could choose to insert the return line from the injection pump into a container with some fluid in the bottom and watch for any air coming out as well as fuel flowing in at idle. No overflowing fuel means there is a problem. If there is it may or may not be your issue but just an age thing that also needs addressed as well. Air on the other hand showing up as bubbles if present. The source of it has to be found.


Now if the hot idle is so rough it could be a cylinder down. You might locate it by loosening each injector nut in turn.