isx cm2250 enigne brake

[hct5]

the engine runs fine after we let it sit over night , on road tests once they engage the engine brake it dies out. i replaced the solenoid and it has been running fine and no longer leaking oil. going to have them road test it but i believe once they hit the engine brake again it will die out and not run once they do that i will get a reading on the oil pressure. what could cause the once engine brake rocker to be moving ? bad rocker?