Guess your base map does not fit your layout. Try finding why it cuts out in the data of the omex. Guess its a stand alone?

If you tap the throttle inlet pressure should rise. Lambda should stay fine. Does the ecu send a longer signal to the injectors then pressure rises (for megasquirt this avaliable.

In a stand alone so much can be set wrong. Maybe you are only running on idle control and as soon as it goes into normal mode it cuts