Misfire

Hi,
after some help please!!

Have a Q3, 2013 with 2ltr tfsi 211bhp with a bad misfire, looks like the engine wants to jump out!
Just driving along and started running rough so pulled over and has bad misfire.
Have tried replacing the coil packs, spark plugs and injectors. Always misfiring on cylinders 1 and 4
but not throwing a code at all. Have had ecu tested and all ok. Replaced the elctro magnetic valve thing for the vvt and still the same.
If engine is revved to 3500 it seems to clear and run ok but below its horrific, and injectors 1 and 4 are shutting off.

Any ideas would be great! Tearing hair out at the moment!

Will double check tomorrow and scope crank sensor and others again

Changed cam sensor today and no difference.
It starts and runs normal for 5 seconds then revs drop and misfire on cylinders 1 and 4. Fault code is open circuit on injector 1 and 4.
Have changed injectors and checked wiring, had the injector drivers in the ecu changed.
When it's running and I clear the codes it runs ok again for 5 seconds then misses and rough! It's looking like ecu problem but don't want to spend £800 on a new one and it not be that!