Well had that accruing fault with these 1.3 Multijet Engines where the engine will go into limp mode at 3000 RPM
It was a stuck waste gate so was getting a over boost error code
A bugger to do as it is half way up the engine on the back of the turbo, a long screw driver is what I used to operate the actuator rod and a good squirt of WD40 and we are back in action
Its only a 10 minute job when you what to do [you tube]
I did this from underneath but some guys remove the airbox and do it from ubove