I've seen where the idle screw meets the throttle shaft stop that the stop will start to bend causing the idle to drop too low and the engine cuts out. Had 2 such incidents happen.
Sounds like you're sucking air between the tank and lift pump. Take a 5 gal. Bucket with fuel, A hose long enough to reach the lift pump and try that. Also check the original fuel lines for rust and deteriorated rubber hoses.
Yes ,known as limp mode. These Cases are notorious to this if you don't run them at high RPMs all the time. The problem is that they don't regen like they should. It's ridiculous that you have to remove the DPF to get it cleaned out. You might be able to get the dealer to send it into...
10 to 1 you have a couple relays down below where you have to pull the battery out to see them. I believe the top one gets ground from the ECU which is the one that gets power to fuses for the start system.. A genius at Case figured if you buried it, it would never fail. Non the less start by...