See more from Ask Carzone 
What's wrong with my Insignia?
What is wrong with my insignia, when I put my foot down to accelerate,it sometimes does not pick up for a couple of seconds, it is a turbo diesel
Our answer:
Hi Paul,
You've not told us the year or engine size of your car, but one common issue with the 2.0-litre CDTi diesel engine is breaking up of the air control flaps in the inlet manifold. So long as they've not damaged the engine internals, it's not a massively expensive fix, and a good mechanic can check that is what it is before taking too much of the engine apart as well.
Have a motoring question? Ask us here!
Ask us anything motoring related and please provide as much information as possible so we can give you the most accurate advice.