Hi all have been complaining to local dealer at last two services (last being major) about low power and bad soot at all revs. Was told nothing wrong. ZD30 CRD motor. Have done some research and found that a number of things can contribute. Not running catch can but soon will be. I have cleaned MAF and found the hose going to the top of the boost controller was split. Obviously a grade mechanics at my local dealer as it was the first thing I noticed. This to has been replaced by myself. Will look at replacing injectors and fuel line soon. After replacing said hose and cleaning MAG sensor used liqui Molly MAF cleaner. At 3500rpm it like rev limiter is kicking in any ideas please. Have reset computer.