91 bluebird hard start 5.9 cummins 12v.
OK it is hard to bleed but starts up runs fantastic but at idle it stalls. The fuel system , mechanical lift pump, check valve, filter and lines all new. No visible leaks. (Obvious ones that is) All copper rubber seals replaced. It loses prime a few seconds on idle unless you catch it in time and feather the throttle. Whatever the leak is it does not affect it off idle it has plenty of smooth power. Any ideas on this before the ripping and tearing of the brand new installation begins?