cutting out on boost over 4000rpm

ok on going problem with my 1.8t bam stage 2 ran fine for a year then garaged for winter,over 4000rpm ish boot it and it cuts completely as though the ignition has been turned off,take foot off gas and comes straight back in.starts and runs ok light throttle ,its shows no codes ive changed the maf,map.coils,crank sensor,plugs even the ecu and the car just kept the engine as it was rebuilt,and had a new turbo, the fuel pump is uprated but has melted a 20amp fuse but the fuel pressure stays at 54psi when it cuts out,and it has a swirl pot in the tank and doesnt show any lean running or misfires.it will hit boost low down but when revs pick up it mostly cuts but sometimes boosts ok

 

Any chance you can scan the ecu for faults?

 

No faults and changed ecu

 

Is it overboosting? Can you check the boost pressure??

 

Same thing in 1st,2nd and 3rd gear? Do the dash lights go out when the engine cuts?

 

My suggestion is to log the fault, using VCDS, in advanced settings, logging engine speed, fuel trim. ignition, airflow, actual lambda, specififed boost and actual, N75.
Run the car into the condition while logging the above, then you cna share the csv file for further analysis.

Else it is very difficult to get help.

 

Il try that when I put a gearbox in as it blew the diff