R32 gtst power loss

[Skileen]

So i scored a R32 gtst the other day, the turbo is going (can hear it spooling) ,and it runs good untill about 4500-5000 revs then theres a sudden loss of power, the sound changes and the car kinda shakes, it does this in every gear, ive also noticed the petrol usage is very high also. I dont know too much about cars so any suggestions would be appreciated =)

[bigbird]

Do you have a boost gauge on the car - have you been able to see how much boost it is able to make - does it go up and down? It might not be a blown turbo just yet.

[Skileen]

Yes i do, its stock boost, does about 0.6 bar. Could it be the Spark Plugs?