Lowkey_RB_Kouki

I have a fuel pressure gauge

The engine is cutting at 5k rpm. If I slowly build the rpm's up it'll rev all the way up to 7k. If I build the rpm's up fast once it hits 5k rpm it'll cut and bog out

It isn't a boost leak and it's a stock ecu at the moment. I've been told the only way to fix this problem is to get a standalone ECU.

Started since the swap was done. No boost leaks, coilpack has been checked/tested, new spark plugs and the plugs have been gapped

I was running 8psi before the new RB25 swap. Stock turbo

If I get into boost sorta fast the engine will cut at 5k rpm. If I slowly get into it it'll let me pass 5k without cutting but won't go over 5psi and also after 5k it'll die sometimes or bog. My shop has checked about everything and they can't find the problem. They told me the only thing I can do now is to run a standalone ECU. I'm fine with that but kinda worried about not being able to run a closed loop so it doesn't waste gas. Any input ? Very much appreciated