[Bennietdi]

I have a golf 4 1.9tdi 2003 model bought it but was in bad shape cleaned out the intake blocked up and removed the catalyst due to being blocked but the vehicle still lacks power turbo also very noisy and can year the turbo shuddering when changing at about 2500 rpm is this normal?

 

[chittychittybangbang]

Shuddering at a certain rpm is often a boost leak. Do a full boost leak test. Also look through the checklist for low power. This involves checking the VNT actuator, all vacuum lines, and solenoids. If you're stuck or find the problem, please post a follow up.
welcometomyturbodies

 

[Robotek]

Yes, the vacuum lines always break up or leak with age and miles. There are a bunch of thinks that can cuse low power, here's the checklist: http://www.myturbodiesel.com/1000q/multi/low-power-fix-TDI.htm