Holden Commodore 2010: rough on gas

Over the last year my 2010 dual-fuel VE Commodore sedan had intermittent problems when running on gas. Sometimes the engine runs very rough and vibrates as if one of the gas injectors is not working. The engine check light comes on and I have to pull over, switch the engine off and switch over to petrol. No error codes are recorded. Under warranty they have replaced injectors, bench tested and serviced injectors, replaced gas pressure switch and carried out a compression and leak down test, but all to no avail. Now the dealer is suggesting I drive it there while experiencing the problem. I have endeavoured to do that only for the fault to rectify itself before I get there. Can you offer any suggestions as to its cause and what to do next? I am desperate for a resolution to the problem. This has gone on far too long.