Brothers car is dropping off boost and smokie then for a few seconds during!

Only happens the odd times when accelerating in 5 gear ,

I'm thinking turbo what's people's taughts?

Sounds like sticky turbo vanes. Do a search on here as there is plenty of reading.

Try searching for 'Mr Muscle Oven Cleaner' too

How many miles has it done?

A 2005 MkII is an early car, almost 8 years old now...

Ye it's a mark ll. it's done 165k km so just over 100k miles.

try also forte turbo cleaner

Smoky also.Thats clogged up and needs a good clear out.As said there is a Mr Muscle solution or a diesel cleaner/additive that will soon sort that out after a good old Italian tune up