2015 F115XB only runs on 1 and 4

[sansig1976]

I have this friend of mine that has a F115XB motor that he had problems with last fall. He started messing with it himself, changed the fuel filters, VST filter, and nothing helped. I took a look at it and found it was not running on 2 or 3, but it has spark on all 4. I swapped the coils and leads, it was still not running on 2 and 3. I swapped the #1 injector with the #2 injector, and still not firing on 2 and 3 although #2 now comes and goes. I took all 4 injectors off and cleaned them, swapped them around and yet still not firing on 2 and 3, where #2 is still occasionally coming and going. Fuel pressure is good and steady, VST looked clean inside. Even though it has spark it seems like it's something weird and electrical preventing it from running on 2/3.

Curious if anyone else has seem something similar?

[boscoe99]

If two of the four cylinders were not firing then why were the fuel filters and the VST filter changed? All four injectors share the same fuel filters and VST filter.

If all four cylinders are firing why were the coils and leads changed?

Someone, somewhere has seen something similar. Hard to find that guy.

Why not go about intelligently trouble shooting the system? Starting with a service manual. Do you have it? Your friend actually.