X15 misfire codes 1, 2, 3

[Dieseltech53]

I have an x15 565 on a diet that keeps throwing misfire codes (attached) cause unknown after driving for cylinders 1,2,3. Won't throw them while idling. Have replaced exhaust gas pressure sensor, injector harness (due to oil in the plug), updated ecm calibration, tried wiggling the harness to see if codes come up, as well as moving injectors with no change. I also has a new head that was put on last fall. It passes injector performance tests. But struggling to find anyone around me with the capability to test injectors. Trying to figure out what my next move should be between getting injectors tested, removing head to inspect valves, or something I'm missing. It started as just cylinder 2 and now has moved to 1 and 3 as well.