I was not aware anymore that the ignition cables cross over. This makes a fault in the ignition system a lot less likely.
Then I would really have a look at the fuel system. Are these the cylinders the farthest away from the entry of the fuel line?
I have heard from ( very powerfull) engines breaking because the cylinders on the end of the rail where leaning because they did not get enough fuel anymore.
Maybe also something is wrong inside the fuel system that prevents the fuel from flowing easy ( can be something as easy as a swollen rubber line). The pump itself should have more than enough pressure to run the engine in idle.
Thinking about this, these are all faults that would appear under full power more than under idle....
If you restart the engine instantly after the cylinders where gone, what happens then? And, what happens if you rev the car up?
Also check the electrical connection to the injector valves. Maybe you have some sort of verdigris or so that prevents the valves from opening the whole time. Also check the side towards the ECU. As soon as the engine gets warmer, the opening time gets shortened, and then they just do not let enough fuel pass for an ignition.
