Volvo V40 TD Trouble

[Volksy]

My old school mate has contacted me with a problem with his Volvo V40 - 1.9 TD (52 plate)

 

It seems the turbo isn't spinning up until quite late in the rev range, and then only for a short burst before it kicks out again. this leads to erratic progress at the least.

My theory is that the waste-gate actuator is sticking, or possibly a MAF sensor fault? Anyone know any quick fixes for these? Or anything obvious I haven't considered?

There's no smoke, so I'm assuming that it's not about to nom nom it's engine oil and blow itself to smithereens!

 

I've not looked at the car yet, it's miles away. So any ideas/theories would be great!

[oman5]

any wooshing noise when accelerating, pointing to leak in the intercooler pipes? check for split pipes anyway just to eliminate this.

[Volksy]

As for as I'm aware, there are no undue noises, but then my mate has quite limited mechanical aptitude where it comes to these things!