loss of power and boost at 5k 0.5 psi

[littledude79]

Hi guys newbie here
Hope ing someone with the right know how could help me

I have a stage 2 lcr with fair few mods list below

Forge tip
3" down pipe
Sports 200cel cat
And performance exhaust at the back
Ko4 turbo and manifold
Bam injectors
Fmic
N249 bypass
Stage 2 map
Cone air filter

The car its self runs great to 5k holds 18psi
But soon as it hits 5k the car seems to loss alot of power and boost pretty much drops straight away to 0.5psi

There no eml cell
If check the n75 valve and maf and as not resolve the issue
Also check vac lines all ok there
Im well and truly stump with it
Any advice would be greatfull as love the car

 

[ibizacupra]

fault codes present?

 

[littledude79]

Thanks for the reply no fault codes not able to get to a specialist atm

 

[littledude79]

Update had it scan today and there are no fault codes stored on the ecu

But now its spluttering under full boost dont boost her and she drives fine