running problem 480 turbo

[damon]

i currently have a 480 turbo that has developed a loss of power when it reaches 4 thousand revs all the way through to the red but it only happens in 3rd 4th & 5th its had a full service and there is no leaks from manifolds and compresion is fine somebody tell me what is wrong before i kill the car?

[Peter Milnes]

Check the hoses from the turbo to the inlet manifold for splits and internal collapses. This is a fairly common cause of your symptoms.

All the best, Peter

[damon]

i'll give that a try and let you know.
thanks damon