Problem past 3000rpm

[DmccaC]

My 05 Sri 150 brake pre facelift has the engine management light on, I tried cleaning the egr valve and puttin another 2nd hand one in, still dead in power and won't rev past 3000! I plugged the computer in and cleared all the faults, then away it went the best full revs and loads of power! But if I turn the car on and off again I'm back to square one! Any ideas or suggestions where I should go from here? All help appreciated! Thanks in advance...

[Beardy]

What were the fault codes you got?

[Leemarksmith]

Boost solenoid issue, check the pipes for splits...

[m8internet]

Why change the EGR Valve when the Engine Management light is on?
Are you confusing the Emissions Warning light?

[DmccaC]

Yes sorry, it's the emissions light! On the right hand side of speedometer!?

[DmccaC]

Turns out somebody has been into the wiring loom presuming to fiddle something in order for it to simply jus run! No the whole loom has to be stripped which is very disheartening for me! Anyone any input to this..:/