Evo3 rev-ing problem

[nclim]

I'm currently facing problem with my E3 engine whereby the rev stuck at 5k rpm.

I checked mostly all compartment which is related to spark and fuel.
*fuel pump (working)
*spark plug (working)
*power unit (working)
*airflow sensor (working)
*plug cable and connector (working)
*ecu (working)
*airflow piping and necessary piping (checked and all seems to be well attached)
*intercooler piping (will check today)

Above mentioned stuff, i replace with a exact same working unit which is from other engine.
Problem still occur. Car boost from 1-4.5k rpm and stuck at 5k rpm.

So i just wanna seek advice from you guys, is there any other possibility that cause this prob on my evo3 engine?

Thanks in advance

regards,